[BUG] Cowork shows "Virtualization is not enabled" on Windows 10 Pro despite Hyper-V fully enabled

Same issue on Dell Latitude 7490.

1. The log lines: yukonSilver not supported (status=unsupported) and VM not supported (win32/x64)
2. Claude Desktop version: 1.1.3918.0
3. Windows 11 Pro with Hyper-V is confirmed active

Same issue on a Gigabyte motherboard, was work a day ago, updated and now says virtualization not enabled.

Same log line about yukonSilver not supported:

Log extract:
2026-02-21 08:20:10 [info] [deleteVMBundle] Reinstall files deleted (sessiondata.img and rootfs.img.zst preserved)
2026-02-21 08:23:29 [info] [cleanupVMBundleIfUnsupported] yukonSilver not supported (status=unsupported), checking for stale bundle...
2026-02-21 08:23:29 [info] [deleteVMBundle] Deleting reinstall files from C:\Users\[REDACTED]\AppData\Roaming\Claude\vm_bundles\claudevm.bundle
2026-02-21 08:23:29 [info] [deleteVMBundle] Reinstall files deleted (sessiondata.img and rootfs.img.zst preserved)
2026-02-21 08:23:32 [warn] [startVM] VM not supported (win32/x64), skipping
2026-02-21 08:23:32 [info] [Callbacks] Initializing VM event callbacks...
2026-02-21 08:23:32 [info] [VM] Loading vmClient (TypeScript) module...
2026-02-21 08:23:32 [info] [VM] Module loaded successfully
2026-02-21 08:23:32 [info] [Callbacks] VM event callbacks initialized
2026-02-21 08:23:33 [warn] [startVM] VM not supported (win32/x64), skipping

I am having the same issue "Virtualization is not enabled
Claude's workspace requires hardware virtualization (Hyper-V). Enable virtualization in your computer's BIOS/UEFI settings, then restart.". I have enabled Hyper-V, but I still get the same error. Initially, when i installed it, I did not have this error.

Same issue on Windows 11 Pro on a Z590 Aorus Elite Gigabyte motherboard, also tried stopping VirtualBox services

Same issue here.

System:

• Windows 11 Pro (German locale)
• Intel Core i5-12600K
• MSI MPG Z690 EDGE WIFI
• 32 GB RAM
• Claude Desktop 1.1.3918 (fresh install)

Verification – everything is enabled:

• Intel Virtualization Technology enabled in BIOS (confirmed in MSI Click BIOS 5 → OC → CPU Features)
• Intel VT-D enabled in BIOS
• Hyper-V enabled in Windows Features (all sub-options)
• Virtual Machine Platform enabled
• Windows Hypervisor Platform enabled
• bcdedit shows hypervisorlaunchtype Auto
• systeminfo confirms: "A hypervisor has been detected"
• Task Manager → CPU → Virtualization: Enabled
• Enable-WindowsOptionalFeature -Online -FeatureName Microsoft-Hyper-V -All returns Online: True

Steps taken:

1. Enabled virtualization in BIOS
2. Enabled all Hyper-V / VM features in Windows
3. Set bcdedit /set hypervisorlaunchtype auto
4. Multiple full restarts
5. Complete uninstall + fresh reinstall of Claude Desktop

Error persists unchanged: "Virtualization is not enabled. Claude's workspace requires hardware virtualization (Hyper-V)."

I can confirm this issue on my Dell machine as well.

Dell Latitude 3420 after updating to 1.1.3918.

I spent quite a bit of time debugging it, and my results match the original report very closely:

• Hyper-V services are running (hns, vmcompute, vmms, SharedAccess)
• Hyper-V / Virtual Machine Platform / Windows Hypervisor Platform are enabled
• bcdedit /set hypervisorlaunchtype auto is set
• BIOS virtualization is enabled (Intel VT-x / VT-d)
• Cowork still shows: “Virtualization is not enabled”

Additional notes from my troubleshooting:

• I initially saw HNS / ICS-related errors and reset the Windows network stack
• After reset, Cowork no longer throws the earlier network errors
• Now Cowork only shows the virtualization warning, even though Hyper-V is enabled and running
• Event Viewer shows Hyper-V virtual switches (including Default Switch and cowork-vm-vnet) being created successfully, but CoworkVMService still logs repeated “Incorrect function” errors

This looks like a false negative in Cowork’s virtualization detection (or a Windows-specific compatibility issue in the latest version), rather than an actual BIOS/Hyper-V configuration problem.

Environment:

• Dell PC
• Windows 11 Pro Insiders (Beta) 25H2 26220.7872
• Claude Desktop / Cowork (latest)

If needed, I can provide:

• systeminfo Hyper-V output
• Event Viewer logs (HNS / Hyper-V / CoworkVMService)
• Screenshots of the Cowork warning

I can reproduce this on Windows 10 Pro as well (different hardware).

My environment

• Windows 10 Pro (build 19045)
• ASUS Rampage V Extreme
• Intel i7-5930K
• Latest Claude Desktop (fresh install)

What I verified

• BIOS virtualization is enabled (Intel VT-x)
• Task Manager shows Virtualization: Enabled
• Windows Features enabled:

• Hyper-V (with subcomponents)
• Virtual Machine Platform
• Windows Hypervisor Platform
• Ran as Administrator:

• bcdedit /set hypervisorlaunchtype auto (successful)
• systeminfo confirms:

• "A hypervisor has been detected. Features required for Hyper-V will not be displayed."
• Hyper-V virtual adapters exist, including:

• vEthernet (cowork-vm-vnet)

Current behavior

Claude Cowork still shows:

• "Virtualization is not enabled"

Extra notes

• In AppData\Local\Claude\Logs I only see a chrome-native-host log (MCP/Chrome integration), and I do not see a Cowork/VM log being created.
• I also see MCP connection errors in the UI (mcp-registry, Claude in Chrome), but Hyper-V itself appears to be working correctly.

This looks like a false virtualization detection on Windows 10, not a BIOS/Hyper-V configuration issue.

Dell PC

Edition Windows 11 Pro
Version 23H2
OS build 22631.6199
Experience Windows Feature Experience Pack 1000.22700.1108.0
Claude 1.1.3918 (a4b368) 2026-02-20T23:13:32.000Z

Virtualization is not enabledClaude's workspace requires hardware virtualization (Hyper-V). Enable virtualization in your computer's BIOS/UEFI settings, then restart.

PS C:\WINDOWS\system32> Get-WindowsOptionalFeature -Online | Where-Object {$_.FeatureName -like "*Hyper*"}

FeatureName : HypervisorPlatform
State       : Enabled

FeatureName : Microsoft-Hyper-V-All
State       : Enabled

FeatureName : Microsoft-Hyper-V
State       : Enabled

FeatureName : Microsoft-Hyper-V-Tools-All
State       : Enabled

FeatureName : Microsoft-Hyper-V-Management-PowerShell
State       : Enabled

FeatureName : Microsoft-Hyper-V-Hypervisor
State       : Enabled

FeatureName : Microsoft-Hyper-V-Services
State       : Enabled

FeatureName : Microsoft-Hyper-V-Management-Clients
State       : Enabled

Same issue. Does anybody got workaround?

Confirming the same issue on Windows 11 Pro (Build 26200).

Cowork tab shows "Virtualisierung ist nicht aktiviert" (German locale) despite Hyper-V being fully operational.

Verification via PowerShell (non-admin):

• (Get-CimInstance Win32_ComputerSystem).HypervisorPresent → True
• - vmcompute service → Running
• - - vmms service → Running (StartType: Automatic)
• - - - (Get-ComputerInfo).HyperVisorPresent → True

Environment:

• Windows 11 Pro 10.0.26200
• - Claude Desktop (latest, German locale)
• - - Hyper-V services fully running, WSL2 functional

same issue.
I got it to work yesterday after the latest update, and it not working again now.

same issue; worked this morning for like 1h, took a break for 2h, came back to laptop, opened claude, got Claude's workspace requires hardware virtualization (Hyper-V). Enable virtualization in your computer's BIOS/UEFI settings, then restart.

Win11, Thinkpad T450s.
I feel empty...

same issue.
Yoga Book 9i Gen 9 , Windows 11

Anyone found a solution?

Windows 11 Pro, Dell Pro Max 16 Plus, Intel
Hyper-V, HypervisorPlatform, Containers, VirtualMachinePlatform all enabled
vmms and vmcompute both running
hypervisorlaunchtype = Auto
Hypervisor detected via systeminfo
Error persists regardless

Same issue here. Cowork was working fine yesterday, broke today without any changes on my end — likely caused by an auto-update.

Environment: LG Gram, Windows 11 Pro Build 26200, Intel i7-1360P, 32 GB RAM, Claude Desktop 1.1.3918 (MSIX), NordVPN installed (disabled during testing — no change).

Everything is enabled and verified: HypervisorPresent = True, hypervisorlaunchtype = Auto, Hyper-V / HypervisorPlatform / VirtualMachinePlatform all Enabled, vmcompute / vmms / CoworkVMService all Running, HNS network cowork-vm-vnet exists.

But the app reports: yukonSilver unsupported, reason "hardware_virt_disabled". Logs show repeated "VM not supported (win32/x64), skipping". VM bundle was wiped by the app and never re-downloaded.

Tried everything: BIOS check, enabling all Windows features, full reinstall, delete VM bundle, delete sessions, clear cache, disable VPN adapters, restart HNS/CoworkVMService, multiple reboots. Nothing works.

Same Issue on Latitude 7400.

System Details:

• CPU: Intel Core i7-8665U @ 1.90GHz
• OS: Windows 11
• Claude Desktop: Latest version
• Subscription: Pro

What Cowork reports:
"Virtualization not enabled"

What my system actually shows:

• Task Manager → CPU tab shows: Virtualization: Enabled
• All Hyper-V Windows features are Enabled (VirtualMachinePlatform, HypervisorPlatform, Microsoft-Hyper-V and all sub-components)
• bcdedit shows: hypervisorlaunchtype = Auto
• Get-ComputerInfo confirms: HyperVisorPresent = True

Root cause identified:
When running the WMI query that Cowork appears to use for detection:
Get-WmiObject -Class Win32_Processor | Select-Object VirtualizationFirmwareEnabled, VMMonitorModeExtensions, SecondLevelAddressTranslationExtensions

All three values return False. This is a known Windows behavior — once Hyper-V is active and running, these WMI fields return False because the hypervisor abstracts the hardware layer. This is expected and correct behavior on a properly configured system.

Cowork is therefore using an unreliable detection method that produces false negatives on machines where Hyper-V is already running.

Troubleshooting already performed:

• Verified virtualization is enabled in BIOS
• Enabled all Hyper-V Windows features
• Set hypervisorlaunchtype to Auto
• Temporarily disabled Memory Integrity (Core Isolation)
• Performed a clean reinstall of Claude Desktop
• Ran Cowork as Administrator

None of the above resolved the issue. The problem is in Cowork's virtualization detection logic, not in my system configuration.

저도 동일한 문제입니다. 잘되다가 갑자기 안되는데, 확실한 업데이트 관련 버그인것 같습니다.

Same issue. I have a Dell XPS

Same issue on my Lenovo Idea pad but working fine on my MSI Desktop?

Both running 11 pro. similar hardware on both machines.

Did all the checks above and all checks out.

Same issue. Even used AWS to check and having the same with AWS.

Same issue here. Windows 11 Home (25H2, build 26200.7840), ASUS ZenBook, Intel i7-1165G7.

• Intel Virtualization Technology: Enabled in BIOS
• VT-d: Enabled in BIOS
• Hyper-V installed via DISM script (Windows Home)
• VirtualMachinePlatform: Enabled
• HypervisorPlatform: Enabled
• bcdedit hypervisorlaunchtype: Auto
• systeminfo confirms: "A hypervisor has been detected"
• Claude Desktop version: latest (reinstalled fresh)

Error "Virtualization is not enabled" still persists on Cowork tab.

Same issue here:
After troubleshooting with online claude, this is conclusion:

At this point I'd strongly recommend contacting Anthropic support directly — you have clean evidence to share: Hyper-V healthy, Sandbox enabled, no WDAC blocks, no MCP binaries present after reinstall. That's enough for them to identify whether it's a broken installer, a missing runtime download step, or a known bug in 1.1.3918.0.

Same issue here.

Environment:

• OS: Windows 11 Pro (Build 26200)
• CPU: 12th Gen Intel Core i7-12700
• Motherboard: ASUS ROG STRIX B660-I GAMING WIFI
• RAM: 32 GB
• Claude Desktop: 1.1.3918.0 (MSIX)

Virtualization status (all confirmed enabled):

• Task Manager → Virtualization: Enabled
• Hyper-V: Enabled (all sub-features checked in Windows Features)
• Virtual Machine Platform: Enabled
• hypervisorlaunchtype: Auto
• systeminfo: "A hypervisor has been detected"
• Hyper-V services (vmcompute, vmms): Running
• HypervisorPresent: True

Despite all of the above, Cowork shows: "Virtualization is not enabled. Claude's workspace requires hardware virtualization (Hyper-V)."

<html>
<body>
<!--StartFragment--><html><head></head><body><h2>Same issue — Windows 11 Insider Build, Intel Core Ultra 9 285HX</h2>
<h3>Environment</h3>
<ul>
<li><strong>OS:</strong> Windows 11 Pro, Build 26200.7840 (Insider Preview)</li>
<li><strong>CPU:</strong> Intel Core Ultra 9 285HX (24 cores)</li>
<li><strong>RAM:</strong> 127 GB</li>
<li><strong>GPU:</strong> NVIDIA RTX PRO 3000</li>
<li><strong>Claude Desktop:</strong> Latest version (fresh install as of 2025-02-21)</li>
</ul>
<h3>Confirmed working virtualization stack</h3>

Check | Result
-- | --
Task Manager → CPU → Virtualization | Enabled
bcdedit /enum \| findstr hypervisorlaunchtype | Auto
Get-WindowsOptionalFeature -Online -FeatureName Microsoft-Hyper-V-All | Enabled
Get-WindowsOptionalFeature -Online -FeatureName HypervisorPlatform | Enabled
Get-WindowsOptionalFeature -Online -FeatureName VirtualMachinePlatform | Enabled
WSL 2 | Functional (wsl --status returns Default Version: 2)
Hyper-V Manager | Functional, can list/manage switches

<h3>Full troubleshooting steps attempted (all failed to resolve)</h3>
<ol>
<li><strong>BIOS verification</strong> — Intel VT-x confirmed enabled, Task Manager confirms "Virtualisierung: Aktiviert"</li>
<li><strong>Enabled all Windows features:</strong>
<pre><code class="language-powershell">Enable-WindowsOptionalFeature -Online -FeatureName Microsoft-Hyper-V -Alldism.exe /Online /Enable-Feature /FeatureName:VirtualMachinePlatform /Alldism.exe /Online /Enable-Feature /FeatureName:HypervisorPlatform /All
</code></pre></li>
<li><strong>Cleared Cowork app data:</strong>
<pre><code class="language-powershell">Remove-Item -Recurse -Force "$env:APPDATA\Claude Cowork"Remove-Item -Recurse -Force "$env:LOCALAPPDATA\Claude Cowork"
</code></pre></li>
<li><strong>Complete uninstall and reinstall</strong> of Claude Desktop (with reboot in between)</li>
<li><strong>Attempted to remove stale <code>cowork-vm-vnet</code> virtual switch</strong> — consistently returned <code>Access Denied (0x80070005)</code> via:
<ul>
<li><code>Remove-VMSwitch -Name "cowork-vm-vnet" -Force</code></li>
<li>Hyper-V Manager GUI → same error</li>
<li><code>Remove-CimInstance</code> via WMI — same result</li>
<li>After stopping all Claude/Cowork processes</li>
<li>After <code>Restart-Service vmms -Force</code></li>
<li>After clean reboot with Claude disabled from autostart</li>
</ul>
</li>
<li><strong>HNS (Host Network Service) full reset</strong> — this was the only method that successfully removed the switch:
<pre><code class="language-powershell">Stop-Service hns -ForceStop-Service vmms -ForceRemove-Item -Path "C:\ProgramData\Microsoft\Windows\HNS\HNS.data" -ForceStart-Service vmmsStart-Service hns
</code></pre>After this, <code>Get-VMSwitch</code> confirmed <code>cowork-vm-vnet</code> was gone. Only <code>Default Switch</code> remained.</li>
<li><strong>Launched Cowork after clean HNS reset</strong> — same error: <em>"Virtualisierung ist nicht aktiviert"</em></li>
</ol>
<h3>Conclusion</h3>
<p>The virtualization detection logic in Cowork appears to be broken. The entire Hyper-V stack is functional (WSL 2 works, Hyper-V Manager works, VMs can be created manually), but Cowork refuses to start its workspace.</p>
<p>This may be related to #27363 (NAT rule creation failure), but in my case the error occurs even after a completely clean state with no stale switches or NAT rules present.</p>
<h3>Root cause found in logs</h3>
<p>The Cowork VM log at <code>%LOCALAPPDATA%\Packages\Claude_pzs8sxrjxfjjc\LocalCache\Roaming\Claude\logs\cowork_vm_node.log</code> reveals the actual issue:</p>
<pre><code>2026-02-21 13:25:22 [info] [cleanupVMBundleIfUnsupported] yukonSilver not supported (status=unsupported), checking for stale bundle...
2026-02-21 13:26:32 [warn] [startVM] VM not supported (win32/x64), skipping
</code></pre>
<p><strong>The VM is never even attempted.</strong> Cowork's internal compatibility check (<code>yukonSilver</code>) classifies this system as <code>unsupported</code> despite all virtualization features being fully functional. This repeats on every startup — the VM module loads, but <code>startVM</code> is immediately skipped.</p>
<p>This appears to be the same root cause as #25136 and #25142 — the <code>yukonSilver</code> status check incorrectly flags certain Windows builds (in my case, Insider Build 26200) as unsupported.</p>
<h3>Additional MCP errors shown alongside the virtualization error</h3>
<pre><code>⚠ Could not connect to MCP server mcp-registry
⚠ Could not connect to MCP server Claude in Chrome
</code></pre>
<h3>Request</h3>
<p>Please either:</p>
<ol>
<li>Fix the <code>yukonSilver</code> compatibility check to recognize Windows 11 Build 26200 with full Hyper-V support, or</li>
<li>Provide a local override mechanism so users with confirmed working virtualization can bypass this check.</li>
</ol></body></html><!--EndFragment-->
</body>
</html>

Same Issue

Device Name: MSI
Processor: 13th Gen Intel(R) Core(TM) i7-1360P (2.20 GHz)
OS: Windows 11 Pro 25H2
Claude Desktop: Latest version

PS C:\WINDOWS\system32> Get-WindowsOptionalFeature -Online | Where-Object {$_.FeatureName -like "Hyper"}

FeatureName : HypervisorPlatform
State : Enabled

FeatureName : Microsoft-Hyper-V-All
State : Enabled

FeatureName : Microsoft-Hyper-V
State : Enabled

FeatureName : Microsoft-Hyper-V-Tools-All
State : Enabled

FeatureName : Microsoft-Hyper-V-Management-PowerShell
State : Enabled

FeatureName : Microsoft-Hyper-V-Hypervisor
State : Enabled

FeatureName : Microsoft-Hyper-V-Services
State : Enabled

FeatureName : Microsoft-Hyper-V-Management-Clients
State : Enabled

I'm experiencing the same issue on Windows 11 Pro (Build 10.0.26100).

Hyper-V is fully enabled, systeminfo confirms a hypervisor is detected, and all relevant Windows features (Hyper-V, Virtual Machine Platform, Windows Hypervisor Platform) are turned on. Despite this, Cowork still shows the "Virtualization is not enabled" error.

+1, hoping for a fix soon.

Same issue here on Windows 11 Pro

Configuration:

• OS: Windows 11 Pro
• CPU: Intel (VMX Virtualization Technology: Enabled in BIOS/UEFI)
• BIOS: Intel VMX Virtualization Technology → Enabled (verified)
• Hyper-V: Enabled via Windows Features (optionalfeatures)
• WSL2: Installed and working (Ubuntu distro active)
• Docker Desktop: Installed and running (Engine running confirmed)
• Claude Desktop: Latest version (updated today)

Verification:
systeminfo | findstr /i "hyper-v" returns:

Configuration requise pour Hyper-V : Un hyperviseur a été détecté. Les fonctionnalités nécessaires à Hyper-V ne seront pas affichées.

This confirms Hyper-V is fully active, yet Cowork still displays:

"La virtualisation n'est pas activée. L'espace de travail de Claude nécessite la virtualisation matérielle (Hyper-V)."

Steps to reproduce:

1. Enable virtualization in BIOS (Intel VMX)
2. Enable Hyper-V in Windows Features
3. Install WSL2 (Ubuntu)
4. Install and launch Docker Desktop
5. Launch Claude Desktop → open Cowork tab
6. Error persists despite all virtualization prerequisites being met

Cowork tab is completely unusable. Chat and code works fine.

I have same issue on Windows 11 Home, Build 26200, Lenovo 83LY.

This is not a BIOS problem.
This is not a Windows problem.
This is not a hardware problem.

This is almost certainly a Claude Cowork detection bug on your machine. Same is happening on my Dell computer, but HP is perfectly fine. So Anthropic needs to fix this issue with virtualization detection ASAP.

window 11 pro, thinkpad P14s gen5
same error

Same here, I was using cowork just fine last night, now I get the same error message... Win 11 home

The same error is happening to me.
I'm confused.

i have this error too
"Virtualization is not enabled
Claude's workspace requires hardware virtualization (Hyper-V). Enable virtualization in your computer's BIOS/UEFI settings, then restart."

Same issue here. Windows 10 Pro, Claude 1.1.3918, Hyper-V fully enabled and confirmed working.

I traced the root cause in app.asar. The check is in function EPt() at approximately byte offset 3645362:

if (n != null && n.isHardwareVirtEnabled && !n.isHardwareVirtEnabled())
  return { status: ... }

The underlying call is IsProcessorFeaturePresent(PF_VIRT_FIRMWARE_ENABLED) which returns false when the Hyper-V hypervisor is already active — the hypervisor masks the CPU feature flags from the guest OS. This is a known Windows behavior. systeminfo confirms "A hypervisor has been detected" and HypervisorPresent = True, proving VT-x is working, but the feature flag check gives a false negative.

Suggested fix: The check should also query IsProcessorFeaturePresent(PF_VIRT_FIRMWARE_ENABLED) OR verify the hypervisor is already present (e.g. via WMI Win32_ComputerSystem.HypervisorPresent or checking CPUID leaf 1 ECX bit 31). If a hypervisor is already running, virtualization is obviously enabled — the current check has the logic inverted for this case.

Attempted binary-patching !n.isHardwareVirtEnabled() → n.isHardwareVirtEnabled() (replacing ! with a space to preserve byte length), but Claude Desktop installs as an MSIX package under C:\Program Files\WindowsApps\ and Windows enforces package integrity — the app refuses to launch after any file modification, making client-side workarounds impossible.

This also appears to cause the downstream MCP error: "Could not connect to MCP server mcp-registry" since the VM never starts.

Environment:

• Windows 11 Pro
• Claude Desktop 1.1.3918 (a4b368) 2026-02-20
• Intel VT-x and VT-d enabled in BIOS
• Hyper-V, Virtual Machine Platform, and Windows Hypervisor Platform all enabled
• bcdedit /set hypervisorlaunchtype auto applied
• systeminfo confirms: "A hypervisor has been detected"

Same issue here — Windows 11 Pro 25H2 (Build 26200.7840), Hyper-V fully enabled

Environment

• OS: Windows 11 Pro, Version 25H2 (OS Build 26200.7840)
• CPU: Intel Core i7-1185G7 @ 3.00GHz (11th Gen Tiger Lake)
• RAM: 32 GB DDR4
• Machine: Lenovo ThinkPad T14 Gen 2 (Type 20W1)
• Claude Desktop Version: Latest (reinstalled fresh from claude.ai/download on Feb 21, 2026)
• Subscription: Max plan

Virtualization Status (all confirmed enabled)

BIOS:

• Intel Virtualization Technology: On
• Intel VT-d Feature: On

Windows Features (all Enabled):

FeatureName                                State
-----------                                -----
HypervisorPlatform                       Enabled
Microsoft-Hyper-V-All                    Enabled
Microsoft-Hyper-V                        Enabled
Microsoft-Hyper-V-Tools-All              Enabled
Microsoft-Hyper-V-Management-PowerShell  Enabled
Microsoft-Hyper-V-Hypervisor             Enabled
Microsoft-Hyper-V-Services               Enabled
Microsoft-Hyper-V-Management-Clients     Enabled
VirtualMachinePlatform                   Enabled

Services running:

Name             Status  StartType
----             ------  ---------
vmcompute        Running Automatic
vmms             Running Automatic
CoworkVMService  Running Automatic

Hypervisor launch type:

bcdedit /enum | findstr hypervisor
hypervisorlaunchtype    Auto

Task Manager confirms: Virtualization: Enabled

What I tried (none resolved it)

1. Enabled VT-x and VT-d in BIOS
2. Enabled Hyper-V, VirtualMachinePlatform, HypervisorPlatform via PowerShell
3. Enabled HyperV-KernelInt-VirtualDevice and HyperV-Guest-KernelInt
4. Ran DISM /Online /Enable-Feature /All /FeatureName:Microsoft-Hyper-V
5. Ran bcdedit /set hypervisorlaunchtype auto
6. Reset BIOS to factory defaults (F9)
7. Uninstalled and reinstalled Claude Desktop (fresh download)
8. Deleted %AppData%\Claude folder and reinstalled
9. Multiple full restarts after each step
10. No conflicting software (no Docker, VMware, or VirtualBox installed)

Additional context

• Cowork was working before on this machine
• The issue appeared after app auto-update around the same time
• Regular Chat mode works perfectly — only Cowork is affected
• Lenovo Diagnostics confirms all hardware functioning correctly

Error message

Virtualization is not enabled
Claude's workspace requires hardware virtualization (Hyper-V). 
Enable virtualization in your computer's BIOS/UEFI settings, then restart.

Also seeing MCP connection errors:

• "Could not connect to MCP server mcp-registry"
• "Could not connect to MCP server Claude in Chrome"

Same issue here. Cowork was working perfectly on Feb 19, then stopped on Feb 20 with the "Virtualization is not enabled" error.

Environment:

• Windows Home (please confirm/update your exact edition)
• Claude Desktop version: (Claude 1.1.3918 (a4b368) 2026-02-20T23:13:32.000Z)
• CPU: (13th Gen Intel(R) Core(TM) i5-13420H)
• Windows version: (Version 25H2 (OS Build 26200.7840)

What changed:
Two Realtek driver updates installed on Feb 20:

• Realtek Semiconductor Corp. Driver Update (18.4032.2509.1900)
• Realtek Semiconductor Corp. Driver Update (6001.15.162.1)

No other changes were made. Cowork worked fine the day before.

Diagnostic results (all confirmed after troubleshooting):

systeminfo | findstr /i "hyper"
→ Hypervisor enforced Code Integrity
→ A hypervisor has been detected. Features required for Hyper-V will not be displayed.

Get-Service vmcompute
→ Running (had to manually start it, was Stopped after reboot)

wsl --status
→ Default Version: 2, Default Distribution: Ubuntu
(WSL had to be reinstalled — was missing after driver updates)

Get-WindowsOptionalFeature -Online | Where-Object FeatureName -like "*hyper*"
→ HypervisorPlatform: Enabled

Get-WindowsOptionalFeature -Online | Where-Object FeatureName -like "*virtual*"
→ VirtualMachinePlatform: Enabled

bcdedit /enum | findstr hypervisorlaunchtype
→ auto

Summary: BIOS virtualization is enabled, hypervisor is detected, vmcompute is running, WSL2 is installed and working, all relevant Windows features are enabled — but Cowork still shows the "Virtualization is not enabled" error. The error message appears to be a false negative in Cowork's virtualization detection.

I'm experiencing the same issue on my Lenovo ThinkPad.

System Details:

• OS: Windows 11 25H2 (Build 26200.7840)
• CPU: Intel (VT-x and VT-d both enabled in BIOS)
• Hyper-V: Fully enabled (including Management Tools and Platform)
• Virtual Machine Platform: Enabled
• Windows Hypervisor Platform: Enabled
• Windows Sandbox: Enabled

Verification steps completed:

• bcdedit /enum | findstr hypervisorlaunchtype → Auto
• systeminfo | findstr "Hyper-V" → "A hypervisor has been detected"
• Get-Service CoworkVMService → Running
• Get-Service vmcompute → Running
• Memory Integrity (Core Isolation) → Already Off

Key observation:
The %APPDATA%\Claude\logs folder does not exist at all — the Cowork VM never even attempts to initialize. The only file in %APPDATA%\Claude\ is claude_desktop_config.json.

Workaround attempted:
Disabling VBS/Memory Integrity did not resolve the issue since it was already off.

This confirms the root cause mentioned above — IsProcessorFeaturePresent(PF_VIRT_FIRMWARE_ENABLED) returns False despite virtualization being fully functional. Multiple reinstalls of Claude Desktop have not helped. Looking forward to a fix using the correct WHvP API check.

Confirming this bug — Windows 11 Home, Lenovo IdeaPad Flex 5

Same issue here. After some fine working experiencings last night, its down now.
My setup:

• Device: Lenovo IdeaPad Flex 5
• OS: Windows 11 Home, Version 25H2 (Build 26200.7840)
• BIOS: Intel Virtual Technology = Enabled (confirmed in Lenovo Setup Utility)
• Windows Features: Virtual Machine Platform ✅, Windows Hypervisor Platform ✅, Hyper-V ❌ (not available on Home edition)

Exact error sequence — triggered by switching models from Sonnet 4.6 to Opus 4.6 during an active Cowork task:

Error 1:

sdk-daemon not connected

Error 2:

RPC error -1: process with name "eloquent-confident-albattani" already running (id: ca7f51ff-283c-4eeb-b909-5342bdc10eb1)

Error 3 (after full system reboot):

Virtualization is not enabled. Claude's workspace requires hardware virtualization (Hyper-V). 
Enable virtualization in your computer's BIOS/UEFI settings, then restart.

---

Core issue: This is a product responsibility, not a user responsibility

The fundamental problem is not that users need better guidance or workarounds —
it is that Anthropic shipped a product with system requirements that exclude a
significant portion of their target audience without any prior notice.

Windows 11 is the most widely used system among freelancers,
consultants, and knowledge workers — precisely the people Cowork is designed for.
Importantly: this issue is also reported by Windows 11 Pro users with Hyper-V
fully enabled (see #27316, #25136, #25876). This confirms that the root cause
is not simply a missing Windows edition feature — it is a fundamental
architectural instability in Cowork's VM implementation on Windows.

The ask is not "warn users better." The ask is: lower the system requirements.

Cowork should work on Windows 11 Home out of the box. If the current VM
architecture requires Hyper-V, that architecture needs to change — not the
user's operating system. WSL2, which is available on Windows Home, would be
a viable alternative backend worth exploring.

Users should never need to enter BIOS settings, investigate their Windows
edition, or research virtualization technology just to use a standard feature
of a paid product.

---

Additional UX issues to fix:

• Model switching during an active task either needs to work stably — or the

model selector should be disabled/greyed out while a task is running.
Basic UX principle: if an action cannot be safely executed, it should not
be offered. A single model switch should never be able to crash the daemon
and require a full system restart to recover.

• Add a "Reset Cowork" option in settings for recovery without manual

file system intervention.

• Error messages must be human-readable, not raw technical codes. Non-technical

users cannot act on RPC error -1 or sdk-daemon not connected.

Also seeing this issue despite Hyper-V enabled.

Windows 11 Pro
Minisforum MS02 Ultra

#27427

Hey all, thanks for flagging! We're working on this and will have a new version out today, I will update here once it's released

Same issue for me and all virtualization in Bios and Windows was set

same issue here, dell + windows 11 pro

Same issue here.

Environment:

• Claude Desktop Version: 1.1.3918 (a4b368)
• OS: Windows 11 Business, Build 26200
• Machine: Lenovo ThinkPad 21KV001EUS
• Processor: Intel Core (13th/14th Gen), Family 6 Model 170, ~2300 MHz
• RAM: 64 GB

Virtualization status — everything is enabled and confirmed working:

• BIOS: Intel VT-x and VT-d both enabled
• systeminfo reports: "A hypervisor has been detected"
• Virtualization-based security: Running
• Get-Service vmms → Running (Hyper-V Virtual Machine Management)
• Enable-WindowsOptionalFeature -Online -FeatureName Microsoft-Hyper-V -All → Online: True, RestartNeeded: False
• bcdedit /set hypervisorlaunchtype auto has been run
• Multiple full restarts performed

Behavior:
Cowork tab shows "Virtualization is not enabled — Claude's workspace requires hardware virtualization (Hyper-V). Enable virtualization in your computer's BIOS/UEFI settings, then restart." Error persists after all the above steps. Was also previously getting a Plan9/virtiofs mount error when attempting to install plugins:

Error invoking remote method '$eipc_message$_5efcc7ca-2dcb-43ae-957c-f5e4a094120c_$_claude.web_$_CustomPlugins_$_listMarketplaces': Error: RPC error -1: failed to ensure virtiofs mount: Plan9 mount failed: bad address

Hyper-V was not initially installed — after enabling it and rebooting, the vmms service runs fine but Cowork still does not detect virtualization.

+1 Same issue for me as well - was working on previous version, broke after update. Intel Core Ultra 9 288V (Lunar Lake)." This confirms it's a regression
OS Name Microsoft Windows 11 Home
Version 10.0.26200 Build 26200
OS Manufacturer Microsoft Corporation
System Manufacturer HP
System Model HP OmniBook Ultra Flip Laptop 14-fh0xxx
Virtualization-based security Running
Virtualization-based security Required Security Properties Base Virtualization Support
Virtualization-based security Available Security Properties Base Virtualization Support, Secure Boot, DMA Protection, UEFI Code Readonly, SMM Security Mitigations 1.0, Mode Based Execution Control, APIC Virtualization
Virtualization-based security Services Configured Hypervisor enforced Code Integrity, Secure Launch, SMM Firmware Measurement
Virtualization-based security Services Running Hypervisor enforced Code Integrity, Secure Launch, SMM Firmware Measurement, Hypervisor-Enforced Paging Translation
App Control for Business policy Enforced
App Control for Business user mode policy Off
SMM Isolation Level Firmware Protection Version Three
Automatic Device Encryption Support Elevation Required to View
A hypervisor has been detected. Features required for Hyper-V will not be displayed.

same issue here, windows 11 pro

same issue , ROG Strix G614JU, Win 11 Pro Build 26200, Intel 13th gen

same issue here, windows 11 pro

same issue: Asus Z790-Plus,Motherboard, Win11 Pro, Intel i5-13600K

Same issue on ROG Strix G614 JV, Win 11 Home. Even after Hyper-V, Virtual Machine Platform, Windows Hypervisor Platform, and WSL are all enabled. Cowork's VM service (CoworkVMService) is not being properly provisioned during installation

Same issue. Lenovo Thinkpad W541. The error: Virtualization is not enabled
Claude's workspace requires hardware virtualization (Hyper-V). Enable virtualization in your computer's BIOS/UEFI settings, then restart.
My VM log:
2026-02-21 18:05:56 [info] [cleanupVMBundleIfUnsupported] yukonSilver not supported (status=unsupported), checking for stale bundle...
2026-02-21 18:06:23 [warn] [startVM] VM not supported (win32/x64), skipping
2026-02-21 18:06:23 [info] [Callbacks] Initializing VM event callbacks...
2026-02-21 18:06:23 [info] [VM] Loading vmClient (TypeScript) module...
2026-02-21 18:06:23 [info] [VM] Module loaded successfully
2026-02-21 18:06:23 [info] [Callbacks] VM event callbacks initialized
2026-02-21 18:06:26 [warn] [startVM] VM not supported (win32/x64), skipping
2026-02-21 18:06:29 [warn] [startVM] VM not supported (win32/x64), skipping
2026-02-21 18:06:34 [warn] [startVM] VM not supported (win32/x64), skipping
2026-02-21 18:06:36 [warn] [startVM] VM not supported (win32/x64), skipping
2026-02-21 18:06:37 [warn] [startVM] VM not supported (win32/x64), skipping
2026-02-21 18:06:40 [warn] [startVM] VM not supported (win32/x64), skipping
2026-02-21 18:06:46 [warn] [startVM] VM not supported (win32/x64), skipping
2026-02-21 18:08:50 [warn] [startVM] VM not supported (win32/x64), skipping
2026-02-21 18:08:52 [warn] [startVM] VM not supported (win32/x64), skipping
2026-02-21 18:08:54 [warn] [startVM] VM not supported (win32/x64), skipping
2026-02-21 18:08:59 [warn] [startVM] VM not supported (win32/x64), skipping
2026-02-21 18:18:55 [warn] [startVM] VM not supported (win32/x64), skipping
2026-02-21 18:18:57 [warn] [startVM] VM not supported (win32/x64), skipping
2026-02-21 18:19:00 [warn] [startVM] VM not supported (win32/x64), skipping
2026-02-21 18:19:05 [warn] [startVM] VM not supported (win32/x64), skipping
2026-02-21 18:19:11 [warn] [startVM] VM not supported (win32/x64), skipping
2026-02-21 18:19:13 [warn] [startVM] VM not supported (win32/x64), skipping
2026-02-21 18:19:16 [warn] [startVM] VM not supported (win32/x64), skipping
2026-02-21 18:19:20 [warn] [startVM] VM not supported (win32/x64), skipping
2026-02-21 18:21:39 [warn] [startVM] VM not supported (win32/x64), skipping
2026-02-21 18:21:41 [warn] [startVM] VM not supported (win32/x64), skipping
2026-02-21 18:21:43 [warn] [startVM] VM not supported (win32/x64), skipping
2026-02-21 18:21:48 [warn] [startVM] VM not supported (win32/x64), skipping
2026-02-21 18:22:59 [warn] [startVM] VM not supported (win32/x64), skipping
2026-02-21 18:23:00 [warn] [startVM] VM not supported (win32/x64), skipping
2026-02-21 18:23:01 [warn] [startVM] VM not supported (win32/x64), skipping
2026-02-21 18:23:01 [warn] [startVM] VM not supported (win32/x64), skipping
2026-02-21 18:23:03 [warn] [startVM] VM not supported (win32/x64), skipping
2026-02-21 18:23:04 [warn] [startVM] VM not supported (win32/x64), skipping
2026-02-21 18:23:08 [warn] [startVM] VM not supported (win32/x64), skipping
2026-02-21 18:23:09 [warn] [startVM] VM not supported (win32/x64), skipping
2026-02-21 18:23:11 [warn] [startVM] VM not supported (win32/x64), skipping
2026-02-21 18:23:11 [warn] [startVM] VM not supported (win32/x64), skipping
2026-02-21 18:23:12 [warn] [startVM] VM not supported (win32/x64), skipping
2026-02-21 18:23:13 [warn] [startVM] VM not supported (win32/x64), skipping
2026-02-21 18:23:15 [warn] [startVM] VM not supported (win32/x64), skipping
2026-02-21 18:23:16 [warn] [startVM] VM not supported (win32/x64), skipping
2026-02-21 18:23:20 [warn] [startVM] VM not supported (win32/x64), skipping
2026-02-21 18:23:20 [warn] [startVM] VM not supported (win32/x64), skipping
2026-02-21 18:23:48 [warn] [startVM] VM not supported (win32/x64), skipping
2026-02-21 18:23:50 [warn] [startVM] VM not supported (win32/x64), skipping
2026-02-21 18:23:53 [warn] [startVM] VM not supported (win32/x64), skipping
2026-02-21 18:23:58 [warn] [startVM] VM not supported (win32/x64), skipping
2026-02-21 18:25:01 [warn] [startVM] VM not supported (win32/x64), skipping
2026-02-21 18:25:02 [warn] [startVM] VM not supported (win32/x64), skipping
2026-02-21 18:25:03 [warn] [startVM] VM not supported (win32/x64), skipping
2026-02-21 18:25:04 [warn] [startVM] VM not supported (win32/x64), skipping
2026-02-21 18:25:06 [warn] [startVM] VM not supported (win32/x64), skipping
2026-02-21 18:25:06 [warn] [startVM] VM not supported (win32/x64), skipping
2026-02-21 18:25:10 [warn] [startVM] VM not supported (win32/x64), skipping
2026-02-21 18:25:11 [warn] [startVM] VM not supported (win32/x64), skipping
2026-02-21 18:25:30 [info] [stopVM] stopping VM gracefully
2026-02-21 18:25:33 [info] [cleanupVMBundleIfUnsupported] yukonSilver not supported (status=unsupported), checking for stale bundle...
2026-02-21 18:25:37 [warn] [startVM] VM not supported (win32/x64), skipping
2026-02-21 18:25:37 [info] [Callbacks] Initializing VM event callbacks...
2026-02-21 18:25:37 [info] [VM] Loading vmClient (TypeScript) module...
2026-02-21 18:25:37 [info] [VM] Module loaded successfully
2026-02-21 18:25:37 [info] [Callbacks] VM event callbacks initialized
2026-02-21 18:25:40 [warn] [startVM] VM not supported (win32/x64), skipping
2026-02-21 18:25:45 [warn] [startVM] VM not supported (win32/x64), skipping
2026-02-21 18:25:46 [warn] [startVM] VM not supported (win32/x64), skipping
2026-02-21 18:25:47 [warn] [startVM] VM not supported (win32/x64), skipping
2026-02-21 18:25:47 [warn] [startVM] VM not supported (win32/x64), skipping
2026-02-21 18:25:49 [warn] [startVM] VM not supported (win32/x64), skipping
2026-02-21 18:25:50 [warn] [startVM] VM not supported (win32/x64), skipping
2026-02-21 18:25:54 [warn] [startVM] VM not supported (win32/x64), skipping
2026-02-21 18:25:55 [warn] [startVM] VM not supported (win32/x64), skipping
2026-02-21 18:27:24 [info] [stopVM] stopping VM gracefully
2026-02-21 18:27:27 [info] [cleanupVMBundleIfUnsupported] yukonSilver not supported (status=unsupported), checking for stale bundle...
2026-02-21 18:27:30 [warn] [startVM] VM not supported (win32/x64), skipping
2026-02-21 18:27:30 [info] [Callbacks] Initializing VM event callbacks...
2026-02-21 18:27:30 [info] [VM] Loading vmClient (TypeScript) module...
2026-02-21 18:27:30 [info] [VM] Module loaded successfully
2026-02-21 18:27:30 [info] [Callbacks] VM event callbacks initialized
2026-02-21 18:27:33 [warn] [startVM] VM not supported (win32/x64), skipping
2026-02-21 18:27:56 [warn] [startVM] VM not supported (win32/x64), skipping
2026-02-21 18:27:59 [warn] [startVM] VM not supported (win32/x64), skipping
2026-02-21 18:28:01 [warn] [startVM] VM not supported (win32/x64), skipping
2026-02-21 18:28:06 [warn] [startVM] VM not supported (win32/x64), skipping
2026-02-21 18:28:10 [warn] [startVM] VM not supported (win32/x64), skipping
2026-02-21 18:28:11 [warn] [startVM] VM not supported (win32/x64), skipping
2026-02-21 18:28:15 [warn] [startVM] VM not supported (win32/x64), skipping
2026-02-21 18:28:19 [warn] [startVM] VM not supported (win32/x64), skipping
2026-02-21 18:28:53 [warn] [startVM] VM not supported (win32/x64), skipping
2026-02-21 18:28:53 [warn] [startVM] VM not supported (win32/x64), skipping
2026-02-21 18:28:55 [warn] [startVM] VM not supported (win32/x64), skipping
2026-02-21 18:28:55 [warn] [startVM] VM not supported (win32/x64), skipping
2026-02-21 18:28:57 [warn] [startVM] VM not supported (win32/x64), skipping
2026-02-21 18:28:58 [warn] [startVM] VM not supported (win32/x64), skipping
2026-02-21 18:29:02 [warn] [startVM] VM not supported (win32/x64), skipping
2026-02-21 18:29:03 [warn] [startVM] VM not supported (win32/x64), skipping
2026-02-21 18:34:17 [info] [stopVM] stopping VM gracefully
2026-02-21 18:34:20 [info] [cleanupVMBundleIfUnsupported] yukonSilver not supported (status=unsupported), checking for stale bundle...
2026-02-21 18:34:23 [warn] [startVM] VM not supported (win32/x64), skipping
2026-02-21 18:34:23 [info] [Callbacks] Initializing VM event callbacks...
2026-02-21 18:34:23 [info] [VM] Loading vmClient (TypeScript) module...
2026-02-21 18:34:23 [info] [VM] Module loaded successfully
2026-02-21 18:34:23 [info] [Callbacks] VM event callbacks initialized
2026-02-21 18:34:26 [warn] [startVM] VM not supported (win32/x64), skipping
2026-02-21 18:34:31 [warn] [startVM] VM not supported (win32/x64), skipping
2026-02-21 18:34:34 [warn] [startVM] VM not supported (win32/x64), skipping
2026-02-21 18:34:36 [warn] [startVM] VM not supported (win32/x64), skipping
2026-02-21 18:34:41 [warn] [startVM] VM

Deep Investigation: yukonSilver unsupported is a server-side feature flag, not a local detection issue

I spent several hours investigating this exact issue across two machines on the same account. Here are my findings:

Environment Comparison

| Property | Desktop (WORKS ✅) | Notebook (FAILS ❌) |
|----------|-------------------|---------------------|
| CPU | AMD Ryzen 7 3700X | Intel i7-13650HX |
| OS | Windows 11 Pro Build 26200 | Windows 11 Pro Build 26200 |
| Claude Version | 1.1.3918.0 | 1.1.3918.0 |
| Hyper-V | Enabled | Enabled |
| hypervisorlaunchtype | Auto | Auto |
| systeminfo | "A hypervisor has been detected" | "A hypervisor has been detected" |
| CoworkVMService | Running / Automatic | Running / Automatic |
| vmcompute / vmms | Running | Running |
| HCS DLLs | Present | Present |
| smol-bin.x64.vhdx | Present | Present |
| WinNat | Running / Automatic | Running / Automatic |
| Same account | Yes | Yes |

Root Cause: Server-Side Feature Flag

The Cowork log on the failing notebook shows:

[cleanupVMBundleIfUnsupported] yukonSilver not supported (status=unsupported), checking for stale bundle...
[startVM] VM not supported (win32/x64), skipping

This repeats on every single startup attempt. The VM module loads successfully but never attempts to start the VM because yukonSilver is flagged as unsupported.

Key Evidence: Desktop Had the SAME Error Until Today

The desktop log reveals that it also had yukonSilver unsupported from January 26 through February 21 morning:

2026-01-26 21:50:47 [info] [cleanupVMBundleIfUnsupported] yukonSilver not supported (status=unsupported)
2026-01-27 19:11:51 [info] [cleanupVMBundleIfUnsupported] yukonSilver not supported (status=unsupported)
... (continued daily through Feb 15)
2026-02-21 10:16:54 [info] [cleanupVMBundleIfUnsupported] yukonSilver not supported (status=unsupported)
2026-02-21 10:17:05 [warn] [startVM] VM not supported (win32/x64), skipping

Then suddenly at 11:45 on Feb 21, after a reinstall, the desktop started working:

2026-02-21 11:45:56 [info] [VM:start] Copying smol-bin.x64.vhdx to bundle
2026-02-21 11:45:56 [info] [VM:start] Windows VM service configured
2026-02-21 11:46:08 [info] [VM] Network status: CONNECTED
2026-02-21 11:46:08 [info] [VM] API reachability: REACHABLE
2026-02-21 11:46:13 [info] [VM:start] Startup complete, total time: 94844ms

Proof It's Not Local

The status unsupported is not stored locally. I verified by:

1. Completely uninstalling Claude (Remove-AppxPackage)
2. Deleting ALL data directories (%APPDATA%\Claude, %LOCALAPPDATA%\Claude, %LOCALAPPDATA%\Packages\Claude_*)
3. Removing CoworkVMService (sc.exe delete)
4. Removing Cowork HNS networks and VMs
5. Removing all NetNat rules
6. Restarting Hyper-V services
7. Rebooting the PC
8. Fresh install from claude.ai/download

Result: First log entry after clean install is still yukonSilver not supported (status=unsupported).

No local file contains the string "yukon" — the status comes from a remote feature flag (likely GrowthBook, as seen in main.log: [growthbook] loaded 27 features).

Impact

The error message displayed to users — "Virtualization is not enabled. Enable virtualization in your computer's BIOS/UEFI settings" — is completely misleading. Virtualization is fully enabled and working. Users are wasting hours troubleshooting BIOS settings, Hyper-V features, and network configuration when the actual blocker is a server-side feature flag they have no control over.

Request

1. Fix the feature flag so yukonSilver is marked as supported for Windows machines that meet all requirements
2. Or at minimum, change the error message to accurately reflect the issue (e.g., "Cowork is not yet available for your device" instead of "Virtualization is not enabled")
3. Clarify what criteria determine yukonSilver support status

System Details (Failing Notebook)

• Model: ASUS ROG Strix G614JU
• CPU: 13th Gen Intel Core i7-13650HX @ 2600 MHz
• RAM: 16 GB
• OS: Windows 11 Pro, Build 26200
• Claude: 1.1.3918.0 (MSIX)
• Hyper-V: Fully enabled (all sub-features)
• VPN: NordVPN installed but disabled during testing

Hey all, we just pushed a new version (v1.1.3963). It may take a few minutes to be available for update, but please give it a try and let us know if you're still hitting this!

Hey all, we just pushed a new version (v1.1.3963). It may take a few minutes to be available for update, but please give it a try and let us know if you're still hitting this!

Fixed!

Fixed is, all my work history is gone. That is expensive issue

still not working properly. We are getting this error now: RPC error -1: failed to ensure virtiofs mount: Plan9 mount failed: bad address

Fixed is, all my work history is gone. That is expensive issue

@mortendotno from the other issue it seems like you might have deleted %APPDATA%/Claude? That's where the history is stored, if you happen to have the old version in the recycle bin would recommend trying to restore it

è uscito un aggiornamento adesso. RISOLTO

> Fixed is, all my work history is gone. That is expensive issue @mortendotno from the other issue it seems like you might have deleted %APPDATA%/Claude? That's where the history is stored, if you happen to have the old version in the recycle bin would recommend trying to restore it

No, but i did a copy of folder "local-agent-mode-sessions" not sure where to place it if that was the correct one.

Edit: Browse plugins -
Failed to load marketplaces
Error invoking remote method '$eipc_message$_bef7c374-81cd-41ac-95ed-1302a463a1c2_$_claude.web_$_CustomPlugins_$_listMarketplaces': Error: RPC error -1: failed to ensure virtiofs mount: Plan9 mount failed: bad address
Restarting Claude or your computer sometimes resolves this. If it persists, you can reinstall the workspace or share your debug logs to help us improve.

> > Fixed is, all my work history is gone. That is expensive issue > > > @mortendotno from the other issue it seems like you might have deleted %APPDATA%/Claude? That's where the history is stored, if you happen to have the old version in the recycle bin would recommend trying to restore it No, but i did a copy of folder "local-agent-mode-sessions" not sure where to place it if that was the correct one. Edit: Browse plugins - Failed to load marketplaces Error invoking remote method '$eipc_message$_bef7c374-81cd-41ac-95ed-1302a463a1c2_$_claude.web_$_CustomPlugins_$_listMarketplaces': Error: RPC error -1: failed to ensure virtiofs mount: Plan9 mount failed: bad address Restarting Claude or your computer sometimes resolves this. If it persists, you can reinstall the workspace or share your debug logs to help us improve.

Ah got it! I would try going into your %APPDATA% Claude folder and replacing the local-agent-mode-sessions folder with the one you saved (though of course back up the new one as well just in case). And then try quitting and restarting the desktop app

I don't think the plugins issue is related to this one so would recommend reporting that one separately via the Submit Feedback button if it persists!

@JacquesAnthropic after the update to v1.1.3963 it works

I re-installed with admin privileges and that worked. Cowork now workig on lenovo idea pad 5 windows pro11

@JacquesAnthropic after the update to v1.1.3963 it works

It works!!! The update is new.

Thanks all! Going to close out this issue

all lost cowork sessions just got restored for some reason, check it out

Hi, thanks jacques for the setup !
I keep getting a loading of "workspace configuration", that bugs everytime. 3rd time trying (after relaunching claude desktop).

<img width="875" height="105" alt="Image" src="https://github.com/user-attachments/assets/6bbc1e29-6161-4a8f-85fe-b92e71782d30" />

What worries me is that it seems I've lost everything I've worked on. Can't be sure until this "workspace setup" is completed, but if you had the same issue, would love to get some tips.

FYI, I've tried many things earlier today (before the fix), including uninstalling Claude desktop. I hope this did not suppress everything...

OK, configuration worked, its working again but I lost everything... If someone knows how to get things restored, would be much appreciated.

I am having this same issue on a new DELL this morning. Still not working

I am having this same issue on a new DELL this morning. Still not working

Did you try installing the latest update? Available in the "Help" panel of the app.

> I am having this same issue on a new DELL this morning. Still not working Did you try installing the latest update? Available in the "Help" panel of the app.

thank you so much - it fixed - you are amazing - thankyou !

@JacquesAnthropic更新到 v1.1.3963 后即可正常工作。

Thank you very much, thank you all

<html>
<body>
<!--StartFragment--><html><head></head><body><h2>Same issue here — Windows 10 Pro 22H2, all virtualization confirmed working</h2>
<h3>System Specs</h3>

Component | Value
-- | --
OS | Windows 10 Pro 22H2 (Build 19045.6937)
CPU | Intel Core i7-7700K @ 4.20GHz
RAM | 32 GB
Claude Desktop | 1.1.3918 (a4b368) 2026-02-20

<h3>Cowork Error</h3>
<blockquote>
<p>Virtualization is not enabled.
Claude's workspace requires hardware virtualization (Hyper-V). Enable virtualization in your computer's BIOS/UEFI settings, then restart.</p>
</blockquote>
<h3>Troubleshooting performed (all confirmed working)</h3>
<p><strong>1. BIOS — Virtualization enabled</strong></p>
<ul>
<li>Intel VT-x / AMD SVM enabled in ASUS BIOS (Advanced → CPU Configuration)</li>
<li>Task Manager → Performance → CPU → Virtualization: <strong>Enabled</strong> ✅</li>
</ul>
<p><strong>2. Hyper-V Windows Feature — Enabled</strong></p>
<pre><code class="language-powershell">PS&gt; Get-WindowsOptionalFeature -Online -FeatureName Microsoft-Hyper-V

FeatureName : Microsoft-Hyper-V
DisplayName : Hyper-V-Plattform
State : Enabled ✅
</code></pre>
<p><strong>3. Hypervisor launch type — Auto</strong></p>
<pre><code class="language-powershell">PS&gt; bcdedit /enum | findstr hypervisorlaunchtype
hypervisorlaunchtype Auto ✅
</code></pre>
<p><strong>4. Hyper-V services — Running</strong></p>
<pre><code class="language-powershell">PS&gt; Get-Service vmcompute, vmms

Both: Status = Running ✅

</code></pre>
<p><strong>5. Windows Fast Startup — Disabled</strong></p>
<ul>
<li>Disabled via Power Options to ensure clean boot</li>
<li>Performed full shutdown via <code>shutdown /s /t 0</code> and cold boot</li>
<li>No change</li>
</ul>
<p><strong>6. WSL — Checked</strong></p>
<pre><code class="language-powershell">PS&gt; wsl --status

(please fill in result)

</code></pre>
<h3>Conclusion</h3>
<p>Every system-level virtualization check passes. The issue is clearly on the app side — Cowork's platform detection rejects Windows 10 Pro (<code>win32/x64</code>) despite Hyper-V being fully functional. The error message is misleading, suggesting a BIOS issue when in reality it appears to be a platform support / detection bug.</p>

I am still getting the same issue; using a Claude version from 2/11/2026 as a workaround but its very unstable. Lots of issues>

<img width="1152" height="648" alt="Image" src="https://github.com/user-attachments/assets/4b40a2b1-7fbe-4fbb-9988-1c6810184fc3" />

Environment

• Windows 11 Pro, Build 10.0.26200.7840 (x64)
• Installed via winget (Anthropic.Claude)
• Tested on versions 1.1.3963 and 1.1.4010
• Claude subscription: Pro Plan

Symptoms
Only the Chat and Code tabs are visible. No Cowork tab. Setting sidebarMode to "cowork" in claude_desktop_config.json causes the app to fail to launch with the error: "Claude Desktop failed to Launch — We are so sorry, Claude Desktop failed to launch. Please check for updates and try again. If the issue persists, contact support."

Log output (cowork_vm_node.log)

[cleanupVMBundleIfUnsupported] yukonSilver not supported (status=unsupported), checking for stale bundle...
[startVM] VM not supported (win32/x64), skipping
[Callbacks] Swift VM addon not available for callbacks

Troubleshooting steps completed

1. Confirmed Intel VT-x enabled in BIOS
2. Enabled all Hyper-V features (were disabled on first install): Microsoft-Hyper-V-All, VirtualMachinePlatform, HypervisorPlatform — all now Enabled
3. Manually registered and started CoworkVMService using cowork-svc.exe from the resources folder — service ran successfully but made no difference
4. Confirmed smol-bin.x64.vhdx is present in resources folder — VM bundle is there
5. Performed multiple full uninstall → delete AppData → reboot → reinstall cycles
6. Upgraded to 1.1.4010 after clean reinstall
7. Installed WSL2 with Ubuntu — wsl --status confirms WSL2 running correctly

Additional notes

• This is a Squirrel-based install (no MSIX), so the Add-AppxPackage workaround from this thread does not apply
• Forcing sidebarMode: "cowork" in config causes a hard launch failure with the error above, suggesting the app is aware of the mode but crashes when platform detection blocks initialisation
• A second machine built from the same Windows image works correctly with Cowork, suggesting the bug may be triggered by Hyper-V being disabled at the time of first install, with no recovery path even after enabling it and performing clean reinstalls

ked for me on Windows 10 Enterprise 22H2 (Build 19045):**

Despite having all Hyper-V features enabled, VirtualMachinePlatform, HypervisorPlatform, Containers, and Windows Sandbox — the "Virtualization is not available" error persisted across multiple restarts and a fresh Claude Desktop reinstall.

What actually fixed it (all 3 steps were needed):

1. Delete the VM bundle to force a fresh download:
2. ```powershell
3. Get-Process claude | Stop-Process -Force
4. Start-Sleep -Seconds 3
5. Remove-Item "$env:APPDATA\Claude\vm_bundles" -Recurse -Force -ErrorAction SilentlyContinue
6. ```
7. Restart the CoworkVMService:
8. ```powershell
9. Restart-Service CoworkVMService
10. ```
11. Launch Claude Desktop as Administrator (right-click > Run as administrator)

After this, the error was gone and Cowork loaded successfully. The key insight is that the VM bundle can get into a bad state and needs to be deleted so the app re-downloads it fresh — combined with running as admin.

Same Issue

why is the issue closed?

I had this exact same issue and managed to fix it. Here is what worked for me:
Check Task Manager: Go to Task Manager > Performance > CPU. Check the bottom right to see if Virtualization is "Disabled". If it is, you need to restart into your BIOS and enable it (look for Intel VT-x, AMD-V, or SVM).
Turn on Windows Features: Search your Windows start menu for "Turn Windows features on or off".
Enable Hyper-V: In that list, make sure to check the boxes for Hyper-V, Virtual Machine Platform, and Windows Hypervisor Platform.
Click OK, let Windows apply the changes, and Restart your PC.
After doing this, the app booted up perfectly for me. Hope this helps!

Same problem here.
Windows 10 PRO.
Claude Version 1.1.6452 (5afc23)

Went all the way through Claude's instructions to try to fix it but no luck. Checked that Virtualization is enabled in Windows.

What's Wrong?
Cowork shows "Virtualization is not enabled. Claude's workspace requires hardware virtualization (Hyper-V). Enable virtualization in your computer's BIOS/UEFI settings, then restart." — despite Hyper-V being fully enabled and all related services running correctly.

Restarting does not resolve the issue.

---

System Info
| Property | Value |
|---|---|
| OS | Windows 10 Pro |
| Claude Desktop version | (add your version here) |
| Installation method | Standard installer |

---

Verification Steps Completed
| Check | Result |
|---|---|
| vmcompute service | ✅ Running |
| vmms service | ✅ Running |
| Hyper-V enabled via Enable-WindowsOptionalFeature | ✅ Done |
| bcdedit hypervisorlaunchtype | ✅ Set to Auto |
| Get-NetNat | ❌ Returns empty |
| Get-HnsNetwork (cowork-vm-nat) | ❌ Returns empty |
| %APPDATA%\Claude\logs folder | ❌ Does not exist — VM never initializes |
| Restarted computer multiple times | ✅ Done |

---

Expected Behavior
Cowork should detect that Hyper-V is enabled and all required services are running, initialize the VM, create the logs folder, and allow access to the workspace.

Actual Behavior
Cowork shows the BIOS error message and never attempts to start the VM. No logs are generated and the %APPDATA%\Claude\logs folder is never created.

---

Steps to Reproduce

1. Install Claude Desktop on Windows 10 Pro
2. Enable Hyper-V via Enable-WindowsOptionalFeature -Online -FeatureName Microsoft-Hyper-V -All
3. Verify vmcompute and vmms services are running
4. Open Claude Desktop and navigate to the Cowork tab
5. Observe the "Virtualization is not enabled" error — VM never initializes

SOLVED I had the same issue and after many tries discovered that the Intel virtualization Service was disabled in the BIOS setup. Enabled and worked.

This issue has been automatically locked since it was closed and has not had any activity for 7 days. If you're experiencing a similar issue, please file a new issue and reference this one if it's relevant.