›_ Claude Code Issues
Claude Code Issues / #25136

[BUG] Cowork tab not showing on Windows 11 Pro x64 — "yukonSilver" marked as unsupported + CoworkVMService cannot be removed

Resolved 💬 48 comments Opened Feb 12, 2026 by hreg123 Closed Feb 13, 2026

Preflight Checklist

  • [x] I have searched existing issues and this hasn't been reported yet
  • [x] This is a single bug report (please file separate reports for different bugs)
  • [x] I am using the latest version of Claude Code

What's Wrong?

<html>
<body>
<!--StartFragment--><html><head></head><body><h1>[BUG] Cowork tab not showing on Windows 11 Pro x64 — "yukonSilver" marked as unsupported + CoworkVMService cannot be removed</h1>
<h2>Preflight Checklist</h2>
<ul>
<li>[x] I have searched existing issues and this hasn't been reported yet</li>
<li>[x] This is a single bug report</li>
<li>[x] I am using the latest version of Claude Desktop</li>
</ul>
<h2>What's Wrong?</h2>
<p>After installing the latest Claude Desktop for Windows (v1.1.2685.0, downloaded Feb 11, 2026), the <strong>Cowork tab does not appear</strong> at all. Only "Chat" is available. The root cause appears to be two interrelated issues:</p>
<ol>
<li><strong><code>yukonSilver</code> VM configuration is marked as "unsupported"</strong> — preventing the VM bundle from being downloaded and the Cowork tab from appearing.</li>
<li><strong><code>CoworkVMService</code> cannot be removed</strong> — the installer detects it as a "conflicting service" but fails to remove it with "Access is denied", even when running as Administrator.</li>
</ol>
<h2>Environment</h2>

Component | Details
-- | --
OS | Windows 11 Pro (Build 26200)
Architecture | x64 (Intel/AMD)
Claude Desktop | v1.1.2685.0 (MSIX install from claude.ai/download)
Claude Plan | Max
Hyper-V | ✅ Enabled
Virtual Machine Platform | ✅ Enabled
Windows Hypervisor Platform | ✅ Enabled
WSL2 | ✅ Installed
Sideloading | ✅ Enabled

<h2>Symptoms</h2>
<ul>
<li>Cowork tab is <strong>not visible</strong> in Claude Desktop — only Chat mode available</li>
<li><code>vm_bundles</code> folder under <code>%APPDATA%\Claude</code> is <strong>never created</strong></li>
<li>Regular Chat mode works without issues</li>
</ul>
<h2>Log Evidence</h2>
<h3>cowork_vm_node.log</h3>
<pre><code>2026-02-11 18:01:09 [info] [cleanupVMBundleIfUnsupported] yukonSilver not supported (status=unsupported), checking for stale bundle...
</code></pre>
<p>This appears to be the primary issue: the VM configuration <code>yukonSilver</code> is incorrectly classified as "unsupported" on a fully capable x64 Windows 11 Pro system with all virtualization features enabled.</p>
<h3>ClaudeSetup.log (repeated across multiple installation attempts)</h3>
<pre><code>WARNING: CoworkVMService already exists (potential conflict)
Conflicting service: true
Removing conflicting CoworkVMService...
WARNING: failed to remove conflicting service: could not open CoworkVMService: Access is denied.
WARNING: old package removal had issues: exit status 1
</code></pre>
<p>The installer successfully installs the MSIX package (<code>INSTALL_SUCCESS</code>), but:</p>
<ul>
<li>Cannot remove the pre-existing <code>CoworkVMService</code> (Access denied even with full elevation)</li>
<li>Cannot remove previous MSIX package cleanly (exit status 1)</li>
<li>Launches via <code>explorer.exe claude://</code> which fails because the protocol handler is not registered</li>
</ul>
<h3>Manual removal also fails</h3>
<pre><code class="language-powershell"># As Administrator:
sc.exe delete CoworkVMService

Result: [SC] OpenService FEHLER 5: Zugriff verweigert (Access denied)

</code></pre>
<p>The service cannot be removed even via Administrator PowerShell or registry manipulation.</p>
<h2>Additional Installation Issue</h2>
<p>The installer has a <strong>user account elevation conflict</strong>: When run by a non-admin user (e.g., "Fritz") and elevated to a different admin account (e.g., "Admin"), the MSIX is downloaded and installed in the Admin user's context (<code>C:\Users\Admin\AppData\Local\Temp\</code>), making it invisible to the original user. The app does not appear in the non-admin user's Start menu.</p>
<p><strong>Workaround found:</strong> Running <code>Add-AppxPackage</code> manually as the target user installs the MSIX correctly for that user.</p>
<h2>Steps to Reproduce</h2>
<ol>
<li>Install Claude Desktop from claude.ai/download on Windows 11 Pro x64 (Build 26200)</li>
<li>Ensure all virtualization features are enabled (Hyper-V, VMP, WHP, WSL2)</li>
<li>Launch Claude Desktop</li>
<li>Observe: Only "Chat" tab visible, no "Cowork" tab</li>
<li>Check <code>%APPDATA%\Claude\logs\cowork_vm_node.log</code> for "yukonSilver not supported"</li>
<li>Check <code>%LOCALAPPDATA%\Temp\ClaudeSetup.log</code> for CoworkVMService access denied warnings</li>
</ol>
<h2>Expected Behavior</h2>
<ul>
<li>Cowork tab should be visible and functional on Windows 11 Pro x64 with all virtualization features enabled</li>
<li><code>yukonSilver</code> should be recognized as supported on this configuration</li>
<li>Installer should be able to clean up its own services</li>
<li>MSIX should install for the user who initiated the setup, not the elevation account</li>
</ul>
<h2>Suggested Fixes</h2>
<ol>
<li><strong>Review <code>yukonSilver</code> platform detection logic</strong> — x64 Windows 11 Pro with Hyper-V should not be classified as "unsupported"</li>
<li><strong>Fix CoworkVMService permissions</strong> — the service should be removable by the installer or at minimum by a system administrator</li>
<li><strong>Fix user context for MSIX installation</strong> — when elevating to a different admin account, install the package for the original user</li>
<li><strong>Register <code>claude://</code> protocol handler</strong> during MSIX installation so the post-install launch works</li>
<li><strong>Add a manual "Reset Cowork" option</strong> in the app settings to allow users to clean up stale services and VM bundles</li>
</ol></body></html><!--EndFragment-->
</body>
</html>

What Should Happen?

Claude should be installed completely and correctly

Error Messages/Logs

See above (sorry, I'm first time here

Steps to Reproduce

Steps to Reproduce

Install Claude Desktop from claude.ai/download on Windows 11 Pro x64 (Build 26200)
Ensure all virtualization features are enabled (Hyper-V, VMP, WHP, WSL2)
Launch Claude Desktop
Observe: Only "Chat" tab visible, no "Cowork" tab
Check %APPDATA%\Claude\logs\cowork_vm_node.log for "yukonSilver not supported"
Check %LOCALAPPDATA%\Temp\ClaudeSetup.log for CoworkVMService access denied warnings

Claude Model

None

Is this a regression?

Yes, this worked in a previous version

Last Working Version

_No response_

Claude Code Version

1.1.2685

Platform

Anthropic API

Operating System

Windows

Terminal/Shell

PowerShell

Additional Information

_No response_

View original on GitHub ↗

48 Comments

github-actions[bot] · 5 months ago

Found 2 possible duplicate issues:

  1. https://github.com/anthropics/claude-code/issues/25034
  2. https://github.com/anthropics/claude-code/issues/25055

This issue will be automatically closed as a duplicate in 3 days.

  • If your issue is a duplicate, please close it and 👍 the existing issue instead
  • To prevent auto-closure, add a comment or 👎 this comment

🤖 Generated with Claude Code

gus-p-williams · 5 months ago

I received the following from Claude:

The problem is definitely the Windows Insider build 26200. Cowork's compatibility detection doesn't recognize this preview build as supported, even though your system has all the right features.

pearson-tfl · 5 months ago

Same issue here — yukonSilver marked unsupported on Windows 11 Pro Insider Preview x64

Environment

  • Claude Desktop Version: 1.1.2998
  • OS: Windows 11 Pro Insider Preview, Build 26300, 25H2
  • CPU: 11th Gen Intel Core i7-1185G7 @ 3.00GHz (x64)
  • RAM: 64 GB
  • Hyper-V: VM Monitor Mode Extensions: Yes; Virtualization Enabled In Firmware: Yes
  • Subscription: Pro

Symptoms

Cowork tab does not appear — only Chat and Code tabs visible

Log Output (%APPDATA%\Claude\logs\cowork_vm_node.log)

Every launch produces the same result:

2026-01-23 01:12:13 [info] [cleanupVMBundleIfUnsupported] yukonSilver not supported (status=unsupported), checking for stale bundle...

VM module loads successfully but yukonSilver is still classified as unsupported:

2026-02-13 08:01:50 [info] [VM] Loading vmClient (TypeScript) module...
2026-02-13 08:01:50 [info] [VM] Module loaded successfully
2026-02-13 08:07:32 [info] [cleanupVMBundleIfUnsupported] yukonSilver not supported (status=unsupported), checking for stale bundle...
hreg123 · 5 months ago

There's a new installer out, the problem seems to be fixed.

I used the installer but had granted the normal user admin rights. The Cowork Tab now shows up.

The Version I installed is Claude 1.1.2998 (1f1d4d) 2026-02-12T20:50:41.000Z

Amrit-Singh-it · 5 months ago

Same issue here — yukonSilver marked unsupported on Windows 11 Business x64

Environment
Claude Desktop Version: 1.1.2998 (1f1d4d)
OS: Windows 11 Business Version 25H2
CPU: Intel(R) Core(TM) i7-1065G7 CPU @ 1.30GHz (1.50 GHz)
System Type: 64-bit operating system, x64-based processor
RAM: 64 GB
Hyper-V: VM Monitor Mode Extensions: Yes; Virtualization Enabled In Firmware: Yes
Subscription: Pro
Symptoms
Cowork tab does not appear — only Chat and Code tabs visible

Log Output (%APPDATA%\Claude\logs\cowork_vm_node.log)

<img width="727" height="398" alt="Image" src="https://github.com/user-attachments/assets/476f5b51-f01f-4c3a-97ba-a436a336ede0" />

aldred-coetzee · 5 months ago

Experiencing the same issue. Cowork tab does not appear — only Chat and Code are visible.

Environment:

  • Claude Desktop: v1.1.2685 (f39a62)
  • Windows 11 Enterprise 25H2, Build 26200.7623
  • HP ZBook Power 16 inch G11 Mobile Workstation
  • Intel Core Ultra 9 185H (2.30 GHz)
  • 64GB RAM, x64-based processor
  • Team plan (premium seat), Cowork confirmed enabled by org admin

Virtualization features (all enabled, confirmed after reboot):

  • Hyper-V ✅
  • Virtual Machine Platform ✅
  • Windows Hypervisor Platform ✅

No conflicting service:

C:\Windows\System32>sc query CoworkVMService
[SC] EnumQueryServicesStatus:OpenService FAILED 1060:
The specified service does not exist as an installed service.

Log output (%APPDATA%\Claude\logs\cowork_vm_node.log):

2026-01-23 18:45:42 [info] [cleanupVMBundleIfUnsupported] yukonSilver not supported (status=unsupported), checking for stale bundle...

This has been repeating on every app launch am on latest version and have tried reinstall

Troubleshooting attempted:

  • Signed out and back in
  • Full app restart
  • Reinstalled latest version as admin
  • Enabled all virtualization features and rebooted
  • Confirmed Cowork enabled by Team org admin
  • Contacted Anthropic support (bot only, no resolution)

This is a corporate-managed machine but with full admin rights and all virtualisation features available and enabled. The VM support check appears to be incorrectly returning "unsupported" for this configuration.

Daniel-DDV · 5 months ago

cowork_vm_node.log - same here

NickyN2 · 5 months ago

I'm experiencing the same issue. Cowork tab does not appear in Claude Desktop.

Environment:

  • Claude Desktop: v1.1.3189 (1b7b58)
  • OS: Windows 11 Pro 25H2 (Build 26200.7840), x64
  • CPU: Intel Core Ultra 9 285K (3.70 GHz)
  • RAM: 48 GB
  • Plan: Pro (monthly)

Virtualization features (all Enabled):

  • Hyper-V (all sub-components)
  • HypervisorPlatform
  • VirtualMachinePlatform

Log output (%APPDATA%\Claude\logs\cowork_vm_node.log):

The issue has been persistent since January 26, 2026. Initially the log showed ERR_MODULE_NOT_FOUND for @ant/claude-swift, which was resolved in a later app update. Since February 13, the VM module loads successfully, but the VM still refuses to start:

[info] [cleanupVMBundleIfUnsupported] yukonSilver not supported (status=unsupported), checking for stale bundle...
[warn] [startVM] VM not supported (win32/x64), skipping
[info] [VM] Loading vmClient (TypeScript) module...
[info] [VM] Module loaded successfully

Enabling Hyper-V, HypervisorPlatform, and VirtualMachinePlatform + rebooting did not resolve the issue. The yukonSilver configuration remains marked as unsupported despite a fully capable x64 system with all virtualization features enabled.

g-i-o-r-g-i-o · 4 months ago

Same problem on
windows 10 pro
claude Claude 1.1.3189 (1b7b58) 2026-02-14T00:09:46.000Z
Plan: Pro (monthly)

maxshurkov · 4 months ago

Проблема актуальна:
Claude 1.1.3189 (1b7b58) 2026-02-14T00:09:46.000Z
windows 11 pro

cmarkwick365 · 4 months ago

Same issue:
❯ Get-Content "$env:APPDATA\Claude\logs\cowork_vm_node.log" | Select-Object -Last 20
2026-02-17 12:08:20 [warn] [startVM] VM not supported (win32/x64), skipping
2026-02-17 12:08:27 [warn] [startVM] VM not supported (win32/x64), skipping
2026-02-17 12:08:36 [warn] [startVM] VM not supported (win32/x64), skipping
2026-02-17 12:08:59 [warn] [startVM] VM not supported (win32/x64), skipping
2026-02-17 12:09:06 [warn] [startVM] VM not supported (win32/x64), skipping
2026-02-17 12:09:13 [warn] [startVM] VM not supported (win32/x64), skipping
2026-02-17 12:09:22 [warn] [startVM] VM not supported (win32/x64), skipping
2026-02-17 12:09:45 [info] [cleanupVMBundleIfUnsupported] yukonSilver not supported (status=unsupported), checking for stale bundle...
2026-02-17 12:11:02 [info] [cleanupVMBundleIfUnsupported] yukonSilver not supported (status=unsupported), checking for stale bundle...
2026-02-17 12:11:12 [info] [cleanupVMBundleIfUnsupported] yukonSilver not supported (status=unsupported), checking for stale bundle...
2026-02-17 12:11:14 [warn] [startVM] VM not supported (win32/x64), skipping
2026-02-17 12:11:14 [info] [Callbacks] Initializing VM event callbacks...
2026-02-17 12:11:14 [info] [VM] Loading vmClient (TypeScript) module...
2026-02-17 12:11:14 [info] [VM] Module loaded successfully
2026-02-17 12:11:14 [info] [Callbacks] VM event callbacks initialized
2026-02-17 12:11:20 [warn] [startVM] VM not supported (win32/x64), skipping
2026-02-17 12:11:33 [warn] [startVM] VM not supported (win32/x64), skipping
2026-02-17 12:11:39 [warn] [startVM] VM not supported (win32/x64), skipping
2026-02-17 12:11:47 [warn] [startVM] VM not supported (win32/x64), skipping
2026-02-17 12:11:56 [warn] [startVM] VM not supported (win32/x64), skipping

TSloper · 4 months ago

2026-02-17 10:18:59 [warn] [startVM] VM not supported (win32/x64), skipping
2026-02-17 10:18:59 [info] [Callbacks] Initializing VM event callbacks...
2026-02-17 10:18:59 [info] [VM] Loading vmClient (TypeScript) module...
2026-02-17 10:18:59 [info] [VM] Module loaded successfully
2026-02-17 10:18:59 [info] [Callbacks] VM event callbacks initialized
2026-02-17 10:19:05 [warn] [startVM] VM not supported (win32/x64), skipping
2026-02-17 10:19:12 [warn] [startVM] VM not supported (win32/x64), skipping
2026-02-17 10:19:22 [warn] [startVM] VM not supported (win32/x64), skipping
2026-02-17 11:50:48 [info] [cleanupVMBundleIfUnsupported] yukonSilver not supported (status=unsupported), checking for stale bundle...
2026-02-17 12:01:27 [warn] [startVM] VM not supported (win32/x64), skipping
2026-02-17 12:01:27 [info] [Callbacks] Initializing VM event callbacks...
2026-02-17 12:01:27 [info] [VM] Loading vmClient (TypeScript) module...
2026-02-17 12:01:27 [info] [VM] Module loaded successfully
2026-02-17 12:01:27 [info] [Callbacks] VM event callbacks initialized
2026-02-17 12:01:33 [warn] [startVM] VM not supported (win32/x64), skipping
2026-02-17 12:01:40 [warn] [startVM] VM not supported (win32/x64), skipping
2026-02-17 12:01:49 [warn] [startVM] VM not supported (win32/x64), skipping
2026-02-17 12:48:39 [warn] [startVM] VM not supported (win32/x64), skipping
2026-02-17 12:48:45 [warn] [startVM] VM not supported (win32/x64), skipping
2026-02-17 12:48:51 [warn] [startVM] VM not supported (win32/x64), skipping
2026-02-17 12:48:57 [warn] [startVM] VM not supported (win32/x64), skipping
2026-02-17 12:49:16 [warn] [startVM] VM not supported (win32/x64), skipping

davidblang · 4 months ago

Same issue here
2026-01-26 17:36:26 [info] [cleanupVMBundleIfUnsupported] yukonSilver not supported (status=unsupported), checking for stale bundle...
2026-01-27 14:13:38 [info] [cleanupVMBundleIfUnsupported] yukonSilver not supported (status=unsupported), checking for stale bundle...
2026-01-27 15:31:35 [info] [cleanupVMBundleIfUnsupported] yukonSilver not supported (status=unsupported), checking for stale bundle...
2026-01-27 15:32:35 [info] [cleanupVMBundleIfUnsupported] yukonSilver not supported (status=unsupported), checking for stale bundle...
2026-01-27 15:43:06 [info] [cleanupVMBundleIfUnsupported] yukonSilver not supported (status=unsupported), checking for stale bundle...
2026-01-27 18:14:30 [info] [cleanupVMBundleIfUnsupported] yukonSilver not supported (status=unsupported), checking for stale bundle...
2026-01-27 18:14:41 [info] [cleanupVMBundleIfUnsupported] yukonSilver not supported (status=unsupported), checking for stale bundle...
2026-01-28 12:02:34 [info] [cleanupVMBundleIfUnsupported] yukonSilver not supported (status=unsupported), checking for stale bundle...
2026-01-28 12:03:36 [info] [cleanupVMBundleIfUnsupported] yukonSilver not supported (status=unsupported), checking for stale bundle...
2026-01-28 12:08:02 [info] [cleanupVMBundleIfUnsupported] yukonSilver not supported (status=unsupported), checking for stale bundle...
2026-01-28 12:08:22 [info] [cleanupVMBundleIfUnsupported] yukonSilver not supported (status=unsupported), checking for stale bundle...
2026-01-28 12:08:32 [info] [cleanupVMBundleIfUnsupported] yukonSilver not supported (status=unsupported), checking for stale bundle...
2026-01-28 12:08:48 [info] [cleanupVMBundleIfUnsupported] yukonSilver not supported (status=unsupported), checking for stale bundle...
2026-01-28 16:09:14 [info] [cleanupVMBundleIfUnsupported] yukonSilver not supported (status=unsupported), checking for stale bundle...
2026-01-28 16:09:23 [info] [cleanupVMBundleIfUnsupported] yukonSilver not supported (status=unsupported), checking for stale bundle...
2026-01-31 16:08:28 [info] [cleanupVMBundleIfUnsupported] yukonSilver not supported (status=unsupported), checking for stale bundle...
2026-01-31 16:09:12 [info] [cleanupVMBundleIfUnsupported] yukonSilver not supported (status=unsupported), checking for stale bundle...
2026-01-31 16:09:22 [info] [cleanupVMBundleIfUnsupported] yukonSilver not supported (status=unsupported), checking for stale bundle...
2026-02-02 15:05:09 [info] [cleanupVMBundleIfUnsupported] yukonSilver not supported (status=unsupported), checking for stale bundle...
2026-02-03 19:07:28 [info] [cleanupVMBundleIfUnsupported] yukonSilver not supported (status=unsupported), checking for stale bundle...
2026-02-03 19:07:41 [info] [cleanupVMBundleIfUnsupported] yukonSilver not supported (status=unsupported), checking for stale bundle...
2026-02-06 13:21:16 [info] [cleanupVMBundleIfUnsupported] yukonSilver not supported (status=unsupported), checking for stale bundle...
2026-02-07 01:22:38 [info] [cleanupVMBundleIfUnsupported] yukonSilver not supported (status=unsupported), checking for stale bundle...
2026-02-07 01:26:15 [info] [cleanupVMBundleIfUnsupported] yukonSilver not supported (status=unsupported), checking for stale bundle...
2026-02-08 20:18:42 [info] [cleanupVMBundleIfUnsupported] yukonSilver not supported (status=unsupported), checking for stale bundle...
2026-02-09 20:19:33 [info] [cleanupVMBundleIfUnsupported] yukonSilver not supported (status=unsupported), checking for stale bundle...
2026-02-12 20:18:47 [info] [cleanupVMBundleIfUnsupported] yukonSilver not supported (status=unsupported), checking for stale bundle...
2026-02-12 20:18:51 [info] [VM] Loading vmClient (TypeScript) module...
2026-02-12 20:18:51 [info] [VM] Module loaded successfully
2026-02-16 04:37:10 [info] [cleanupVMBundleIfUnsupported] yukonSilver not supported (status=unsupported), checking for stale bundle...
2026-02-16 17:46:21 [info] [VM] Loading vmClient (TypeScript) module...
2026-02-16 17:46:21 [info] [VM] Module loaded successfully
2026-02-17 11:12:45 [info] [cleanupVMBundleIfUnsupported] yukonSilver not supported (status=unsupported), checking for stale bundle...
2026-02-17 11:14:53 [warn] [startVM] VM not supported (win32/x64), skipping
2026-02-17 11:14:53 [info] [Callbacks] Initializing VM event callbacks...
2026-02-17 11:14:53 [info] [VM] Loading vmClient (TypeScript) module...
2026-02-17 11:14:53 [info] [VM] Module loaded successfully
2026-02-17 11:14:53 [info] [Callbacks] VM event callbacks initialized
2026-02-17 11:57:54 [warn] [startVM] VM not supported (win32/x64), skipping
2026-02-17 11:58:01 [warn] [startVM] VM not supported (win32/x64), skipping
2026-02-17 11:58:10 [warn] [startVM] VM not supported (win32/x64), skipping
2026-02-17 11:58:21 [warn] [startVM] VM not supported (win32/x64), skipping
2026-02-17 11:58:28 [warn] [startVM] VM not supported (win32/x64), skipping
2026-02-17 11:58:35 [warn] [startVM] VM not supported (win32/x64), skipping
2026-02-17 11:58:44 [warn] [startVM] VM not supported (win32/x64), skipping
2026-02-17 11:59:50 [warn] [startVM] VM not supported (win32/x64), skipping
2026-02-17 11:59:56 [warn] [startVM] VM not supported (win32/x64), skipping
2026-02-17 12:00:03 [warn] [startVM] VM not supported (win32/x64), skipping
2026-02-17 12:43:32 [warn] [startVM] VM not supported (win32/x64), skipping
2026-02-17 12:43:38 [warn] [startVM] VM not supported (win32/x64), skipping
2026-02-17 12:43:45 [warn] [startVM] VM not supported (win32/x64), skipping
2026-02-17 12:43:54 [warn] [startVM] VM not supported (win32/x64), skipping
2026-02-17 12:44:48 [warn] [startVM] VM not supported (win32/x64), skipping
2026-02-17 12:44:54 [warn] [startVM] VM not supported (win32/x64), skipping
2026-02-17 12:45:01 [warn] [startVM] VM not supported (win32/x64), skipping
2026-02-17 12:45:10 [warn] [startVM] VM not supported (win32/x64), skipping
2026-02-17 12:45:34 [warn] [startVM] VM not supported (win32/x64), skipping
2026-02-17 12:45:40 [warn] [startVM] VM not supported (win32/x64), skipping
2026-02-17 12:45:47 [warn] [startVM] VM not supported (win32/x64), skipping
2026-02-17 12:45:56 [warn] [startVM] VM not supported (win32/x64), skipping
2026-02-17 12:53:30 [warn] [startVM] VM not supported (win32/x64), skipping
2026-02-17 12:53:37 [warn] [startVM] VM not supported (win32/x64), skipping
2026-02-17 12:53:44 [warn] [startVM] VM not supported (win32/x64), skipping
2026-02-17 12:53:53 [warn] [startVM] VM not supported (win32/x64), skipping
2026-02-17 12:56:00 [warn] [startVM] VM not supported (win32/x64), skipping
2026-02-17 12:56:06 [warn] [startVM] VM not supported (win32/x64), skipping
2026-02-17 12:56:13 [warn] [startVM] VM not supported (win32/x64), skipping
2026-02-17 12:56:22 [warn] [startVM] VM not supported (win32/x64), skipping
2026-02-17 12:57:44 [warn] [startVM] VM not supported (win32/x64), skipping
2026-02-17 12:57:50 [warn] [startVM] VM not supported (win32/x64), skipping
2026-02-17 12:57:57 [warn] [startVM] VM not supported (win32/x64), skipping
2026-02-17 12:58:06 [warn] [startVM] VM not supported (win32/x64), skipping
2026-02-17 13:18:12 [info] [cleanupVMBundleIfUnsupported] yukonSilver not supported (status=unsupported), checking for stale bundle...
2026-02-17 13:21:35 [warn] [startVM] VM not supported (win32/x64), skipping
2026-02-17 13:21:35 [info] [Callbacks] Initializing VM event callbacks...
2026-02-17 13:21:35 [info] [VM] Loading vmClient (TypeScript) module...
2026-02-17 13:21:35 [info] [VM] Module loaded successfully
2026-02-17 13:21:35 [info] [Callbacks] VM event callbacks initialized
2026-02-17 13:23:22 [warn] [startVM] VM not supported (win32/x64), skipping
2026-02-17 13:23:30 [warn] [startVM] VM not supported (win32/x64), skipping
2026-02-17 13:25:10 [warn] [startVM] VM not supported (win32/x64), skipping
2026-02-17 13:25:16 [warn] [startVM] VM not supported (win32/x64), skipping
2026-02-17 13:25:23 [warn] [startVM] VM not supported (win32/x64), skipping
2026-02-17 13:25:32 [warn] [startVM] VM not supported (win32/x64), skipping

Daniel-DDV · 4 months ago

Anthropics, I love you. And its my own fault for trying to run cowork on a Michaelsoft Binbows machine. But kindly do make it work please. Thx!

everton-o · 4 months ago

Same issue here:

Get-Content "$env:APPDATA\Claude\logs\cowork_vm_node.log" | Select-Object -Last 20
2026-02-13 16:24:01 [info] [cleanupVMBundleIfUnsupported] yukonSilver not supported (status=unsupported), checking for stale bundle...
2026-02-13 16:24:09 [info] [cleanupVMBundleIfUnsupported] yukonSilver not supported (status=unsupported), checking for stale bundle...
2026-02-16 08:59:17 [info] [cleanupVMBundleIfUnsupported] yukonSilver not supported (status=unsupported), checking for stale bundle...
2026-02-17 18:16:55 [info] [cleanupVMBundleIfUnsupported] yukonSilver not supported (status=unsupported), checking for stale bundle...
2026-02-17 18:51:54 [info] [cleanupVMBundleIfUnsupported] yukonSilver not supported (status=unsupported), checking for stale bundle...
2026-02-17 18:51:58 [info] [cleanupVMBundleIfUnsupported] yukonSilver not supported (status=unsupported), checking for stale bundle...

ankitbharadwaj10 · 4 months ago

Just uninstalled claude and reinstalled it, and I can see the cowork tab now.

g-i-o-r-g-i-o · 4 months ago
Just uninstalled claude and reinstalled it, and I can see the cowork tab now.

I have the cowork tab now (top bar)... after reinstalling. Will see if it works after reboot.

<img width="1030" height="357" alt="Image" src="https://github.com/user-attachments/assets/df056ddc-a31e-479e-a7e7-341013ee7175" />

Meowkai123 · 4 months ago

Don't rely on the in-app updater, re-download the installer from the website and installed (without even having to uninstall claude).
Fixed it for me.

nanonandi · 4 months ago

Re-downloading the installer works, but it installs Claude to a different location:

  • Original installer: C:\~\AppData\Local\AnthropicClaude
  • New installer: C:\Program Files\WindowsApps\Claude_1.1.3363.0_x64__pzs8sxrjxfjjc

This causes issues with config files. The old installer reads the config from:
C:\~\AppData\Roaming\Claude\claude_desktop_config.json
While the new one reads from:
C:\~\AppData\Local\Packages\Claude_pzs8sxrjxfjjc\LocalCache\Roaming\Claude\claude_desktop_config.json

However, clicking "Edit Config" still tries to open the old config path, not the new one.

gus-p-williams · 4 months ago

I just re-installed and still co-work does not work:

Environment:

Claude Desktop: v1.1.3189 (latest version as of Feb 18, 2026)
OS: Windows 11 Pro 25H2 (Build 26200.7840), x64
CPU: Intel (model unknown - need to check System Information)
RAM: (amount unknown - need to check System Information)
Plan: Pro (monthly)

Virtualization features (all Enabled):

Hyper-V (all sub-components) - verified via PowerShell: State: Enabled
HypervisorPlatform
VirtualMachinePlatform

Log output (%APPDATA%\Claude\logs\cowork_vm_node.log):
The issue has been persistent since at least February 10, 2026 (Cowork Windows launch date). The log consistently shows:
2026-02-10 14:26:51 [info] [cleanupVMBundleIfUnsupported] yukonSilver not supported (status=unsupported), checking for stale bundle...
2026-02-10 14:26:52 [info] [cleanupVMBundleIfUnsupported] yukonSilver not supported (status=unsupported), checking for stale bundle...
2026-02-11 10:55:06 [info] [cleanupVMBundleIfUnsupported] yukonSilver not supported (status=unsupported), checking for stale bundle...
2026-02-12 10:11:17 [info] [cleanupVMBundleIfUnsupported] yukonSilver not supported (status=unsupported), checking for stale bundle...
[continues repeating...]
2026-02-12 16:19:42 [info] [VM] Loading vmClient (TypeScript) module...
2026-02-12 16:19:42 [info] [VM] Module loaded successfully
The VM module loads successfully, but the VM refuses to start. The yukonSilver configuration is marked as unsupported despite a fully capable x64 Windows 11 Pro system with all virtualization features enabled and verified.
Steps taken:

Enabled Hyper-V, HypervisorPlatform, and VirtualMachinePlatform
Rebooted multiple times
Reinstalled Claude Desktop
Verified virtualization via PowerShell (Get-WindowsOptionalFeature -Online -FeatureName Microsoft-Hyper-V-All shows State: Enabled)

Root cause:
Windows 11 Build 26200 appears to be incorrectly flagged as unsupported by Cowork's platform detection logic. This is consistent with issues #25136, #25142, #25692, and #25829.

System Information:
OS Name: Microsoft Windows 11 Pro for Workstations
OS Version: 10.0.26200 N/A Build 26200
OS Manufacturer: Microsoft Corporation
OS Configuration: Standalone Workstation
OS Build Type: Multiprocessor Free
Product ID: XXX
Original Install Date: 2/12/2025, 8:42:41 AM
System Boot Time: 2/18/2026, 8:57:50 AM
System Manufacturer: Dell Inc.
System Model: Precision 5820 Tower
System Type: x64-based PC
Processor(s): 1 Processor(s) Installed.
[01]: Intel64 Family 6 Model 85 Stepping 7 GenuineIntel ~3912 Mhz
BIOS Version: Dell Inc. 2.41.0, 2/14/2025
Windows Directory: C:\WINDOWS
System Directory: C:\WINDOWS\system32
Boot Device: \Device\HarddiskVolume6
System Locale: en-us;English (United States)
Input Locale: en-us;English (United States)
Time Zone: (UTC-07:00) Mountain Time (US & Canada)
Total Physical Memory: 81,603 MB
Available Physical Memory: 58,383 MB
Virtual Memory: Max Size: 86,723 MB
Virtual Memory: Available: 58,202 MB
Virtual Memory: In Use: 28,521 MB
Page File Location(s): C:\pagefile.sys
Domain: WORKGROUP
Logon Server: XXX
Hotfix(s): 4 Hotfix(s) Installed.
[01]: KB5066128
[02]: KB5054156
[03]: KB5077181
[04]: KB5077869

Virtualization-based security: Status: Running
Required Security Properties:
Available Security Properties:
Base Virtualization Support
Secure Boot
DMA Protection
Secure Memory Overwrite
UEFI Code Readonly
Mode Based Execution Control
APIC Virtualization
Services Configured:
Services Running:
App Control for Business policy: Enforced
App Control for Business user mode policy: Off
Security Features Enabled:
Hyper-V Requirements: A hypervisor has been detected. Features required for Hyper-V will not be displayed.

g-i-o-r-g-i-o · 4 months ago

Is this a VPN problem?

I can't disable the VPN... I get the same error even if I disable the VPN. Claude is obviously whitelisted to bypass the vpn.

<img width="977" height="471" alt="Image" src="https://github.com/user-attachments/assets/86c35386-5120-4b73-8437-04e71c368032" />

mhemry · 4 months ago

Here's a ready-to-paste comment you can add:

---

Environment:

  • OS: Windows 11 Pro, Version 25H2, Build 26200.7840
  • Claude Desktop version: Claude 1.1.3918 (a4b368) 2026-02-20T23:13:32.000Z
  • CPU: Intel Core i9-14900K 3.2 GHz 24-Core Processor
  • Motherboard: Asus Z790 GAMING WIFI7 ATX LGA1700 Motherboard

Virtualization status (all correctly configured):

  • BIOS virtualization: Enabled
  • Hyper-V enabled via PowerShell: Confirmed (RestartNeeded: False)
  • Get-ComputerInfo -Property "HyperV*" returns HyperVisorPresent: True
  • Task Manager → CPU → Virtualization: Enabled

Log output from cowork_vm_node.log:

2026-02-20 20:29:29 [info] [cleanupVMBundleIfUnsupported] yukonSilver not supported (status=unsupported), checking for stale bundle...
2026-02-20 20:29:59 [warn] [startVM] VM not supported (win32/x64), skipping

Steps already tried:

  • Full restart after enabling Hyper-V
  • Checked Settings → System → Advanced → Virtual Workspaces
  • Complete uninstall, fresh reinstall as Administrator

Summary:
Hardware virtualization is fully enabled and confirmed working at the OS level (HyperVisorPresent: True), but the app incorrectly flags win32/x64 as unsupported and shows the error "Claude's workspace requires hardware virtualization (Hyper-V)". This is a newly built desktop PC with no prior Windows installations or conflicting software.

---

2026-02-20 20:29:29 [info] [cleanupVMBundleIfUnsupported] yukonSilver not supported (status=unsupported), checking for stale bundle...
2026-02-20 20:29:59 [warn] [startVM] VM not supported (win32/x64), skipping
2026-02-20 20:29:59 [info] [Callbacks] Initializing VM event callbacks...
2026-02-20 20:29:59 [info] [VM] Loading vmClient (TypeScript) module...
2026-02-20 20:29:59 [info] [VM] Module loaded successfully
2026-02-20 20:29:59 [info] [Callbacks] VM event callbacks initialized
2026-02-20 20:30:00 [warn] [startVM] VM not supported (win32/x64), skipping
2026-02-20 20:30:02 [warn] [startVM] VM not supported (win32/x64), skipping
2026-02-20 20:30:32 [warn] [startVM] VM not supported (win32/x64), skipping
2026-02-20 20:30:33 [warn] [startVM] VM not supported (win32/x64), skipping
2026-02-20 20:30:35 [warn] [startVM] VM not supported (win32/x64), skipping
2026-02-20 20:30:40 [warn] [startVM] VM not supported (win32/x64), skipping

JLoo86 · 4 months ago

[BUG] Cowork VM not supported on Windows 11 Pro x64 with Hyper-V enabled — yukonSilver status=unsupported

Environment:

  • OS: Windows 11 Pro x64 (Build 22631)
  • Claude Desktop version: 1.1.3918.0 (MSIX install)
  • Install location: C:\Program Files\WindowsApps\Claude_1.1.3918.0_x64__pzs8sxrjxfjjc
  • Hyper-V: Fully enabled and active (hypervisor confirmed running via bcdedit and systeminfo)
  • CPU Virtualization: Enabled (confirmed via Task Manager → Performance → CPU)

What's happening:

Cowork tab is visible but fails to start. The VM is being flagged as unsupported despite the system meeting all requirements.

Relevant lines from cowork_vm_node.log:

2026-02-21 14:21:23 [info] [cleanupVMBundleIfUnsupported] yukonSilver not supported (status=unsupported), checking for stale bundle...
2026-02-21 15:23:02 [warn] [startVM] VM not supported (win32/x64), skipping

Additional observations:

  • rootfs.vhdx was missing in early log entries, suggesting the VM bundle never fully downloaded
  • Secondary error also present: Could not connect to MCP server mcp-registry
  • Hyper-V confirmed working: systeminfo returns "A hypervisor has been detected. Features required for Hyper-V will not be displayed."
  • Get-WindowsOptionalFeature -Online -FeatureName Microsoft-Hyper-V-All returns State: Enabled
  • CoworkVMService status: present but not starting due to VM being flagged unsupported
  • MSIX install means app files are protected and no client-side workaround is possible

Expected behaviour:

Cowork should detect win32/x64 with active Hyper-V as a supported platform and proceed to boot the VM.

What I've tried:

  • Verified CPU virtualization enabled in BIOS and Windows
  • Confirmed Hyper-V enabled via PowerShell and Windows Features
  • Confirmed hypervisor is actively running
  • Reinstall of Claude Desktop (no change)

This appears to be the same root cause as #25136 and #25142 — platform detection incorrectly rejecting standard x64 Windows 11 Pro machines. Happy to provide full logs if helpful.

ldovg777-art · 4 months ago

aSame issue after auto-update to v1.1.3918 (a4b368) on Feb 21, 2026.

Cowork was working fine on v1.1.3647 yesterday (Feb 20). After today's update, Cowork shows "Virtualization is not enabled" error.

  • OS: Windows 11 Pro, 25H2, Build 26200.7840, x64
  • - Hyper-V: Enabled (confirmed via DISM and Task Manager)
  • - - Virtualization: Enabled in BIOS

cowork_vm_node.log repeats:
[warn] [startVM] VM not supported (win32/x64), skipping
[info] [cleanupVMBundleIfUnsupported] yukonSilver not supported (status=unsupported)

The VM module loads successfully but never boots. Clear regression from previous version.

jensolafkoch · 4 months ago

Same issue after auto-update to v1.1.3918 (a4b368) on Feb 21, 2026.

Cowork was working fine on v1.1.3647 yesterday (Feb 20). After today's update, Cowork shows "Virtualization is not enabled" error.

Total showstopper!

Ki-Pate · 4 months ago

Same issue here since update.

Virtualisierung ist nicht aktiviert
Claudes Workspace benötigt Hardware-Virtualisierung (Hyper-V). Aktiviere die Virtualisierung in den BIOS/UEFI-Einstellungen deines Computers und starte ihn dann neu.

siiron · 4 months ago

+1 on Version 1.1.3918

stephanechappellier-beep · 4 months ago

Same issue : La virtualisation n'est pas activée.
L'espace de travail de Claude nécessite la virtualisation matérielle (Hyper-V). Activez la virtualisation dans les paramètres BIOS/UEFI de votre ordinateur, puis redémarrez. // PROBLEM KNOW SINCE FEB-11, we are FEB-21, still no solution, and you the bug be distributed through update : SHAME ON YOU ALL.

cerdman · 4 months ago

+1 on Claude 1.1.3918 (a4b368) 2026-02-20T23:13:32.000Z

WiesiDeluxe · 4 months ago

+1 on Version 1.1.3918

MrSneider · 4 months ago

<html>
<body>
<!--StartFragment--><html><head></head><body><h2>Same issue here — Claude Desktop v1.1.3918.0 (latest as of Feb 21, 2026)</h2>
<h3>Environment</h3>

Component | Details
-- | --
OS | Windows 11 Pro 25H2 (Build 26200.7840)
Architecture | x64 (AMD64)
Claude Desktop | v1.1.3918.0 (MSIX)
Claude Plan | Max
Hyper-V | ✅ Enabled (all sub-features)
Virtual Machine Platform | ✅ Enabled
Windows Hypervisor Platform | ✅ Enabled
WSL2 | ✅ Installed (Version 2)
Sideloading / Dev Mode | ✅ Enabled
HyperVisorPresent | True
vmms Service | Running
vmcompute Service | Running

<h3>Log output (cowork_vm_node.log)</h3>
<pre><code>2026-02-21 11:29:56 [info] [cleanupVMBundleIfUnsupported] yukonSilver not supported (status=unsupported), checking for stale bundle...
2026-02-21 11:31:25 [warn] [startVM] VM not supported (win32/x64), skipping
2026-02-21 11:31:25 [info] [Callbacks] Initializing VM event callbacks...
2026-02-21 11:31:25 [info] [VM] Loading vmClient (TypeScript) module...
2026-02-21 11:31:25 [info] [VM] Module loaded successfully
2026-02-21 11:31:25 [info] [Callbacks] VM event callbacks initialized
2026-02-21 11:31:26 [warn] [startVM] VM not supported (win32/x64), skipping
</code></pre>
<h3>Notes</h3>
<ul>
<li>BIOS: Intel Virtualization Tech (VT-x) and Intel VT-D Tech both enabled</li>
<li>Originally Windows 11 Home, upgraded to Pro specifically for Hyper-V/Cowork</li>
<li>Claude Desktop UI shows "Virtualization is not enabled" banner despite all features being correctly configured</li>
<li>This bug persists in v1.1.3918.0 — newer than the originally reported v1.1.2685.0</li>
<li>Chat and Code tabs work perfectly, only Cowork is affected</li>
</ul></body></html><!--EndFragment-->
</body>
</html>

antx0o0 · 4 months ago

+1 Same problem here. It won't boot a virtual machine. Desperate.

steven10924 · 4 months ago

+1 on this issue. Same problem on a fully capable system.
Environment:

OS: Windows 11 Pro (Build 26200)
CPU: Intel Core i7-14650HX
RAM: 32 GB
Hyper-V: Enabled (including Hyper-V Platform + Management Tools)
Virtual Machine Platform: Enabled
Windows Hypervisor Platform: Enabled
BIOS VT-x: Enabled (confirmed via Task Manager → CPU → Virtualization: Enabled)
CoworkVMService: Running
Claude Desktop Version: 1.1.3918 (MSIX)

Log output from cowork_vm_node.log:
[cleanupVMBundleIfUnsupported] yukonSilver not supported (status=unsupported), checking for stale bundle...
[startVM] VM not supported (win32/x64), skipping
What I've tried (none resolved the issue):

Upgraded from Windows Home to Pro
Enabled Hyper-V, VMP, and WHP in Windows Features
Confirmed VT-x enabled in BIOS
Rebooted multiple times
Completely uninstalled and reinstalled Claude Desktop (with admin privileges)
Deleted and recreated the vm_bundles directory

Despite all virtualization features being correctly enabled, Cowork still shows "Virtualization is not enabled" and the VM is marked as unsupported. This appears to be a detection bug — the system meets all requirements but yukonSilver incorrectly classifies it as unsupported.

usenkov · 4 months ago

System Information
Operating System: Windows 11 Pro x64
CPU: Intel Core(TM) i7-10870H @ 2.20GHz (8 cores, 16 threads)
RAM: 64 GB
Claude Desktop Version: Latest (downloaded February 21, 2026 from claude.com/download)
Subscription: Claude Pro

Steps Taken and Verification
I have systematically enabled and verified all virtualization prerequisites:

  1. Windows Features Enabled

All three required features have been enabled via optionalfeatures (Turn Windows features on or off):
• Hyper-V (including Hyper-V Platform and Hyper-V Management Tools) — Enabled ✅
• Virtual Machine Platform (Платформа виртуальной машины) — Enabled ✅
• Windows Hypervisor Platform — Enabled ✅

System was restarted after enabling these features.

  1. BIOS/UEFI Hardware Virtualization

Intel VT-x is enabled in BIOS. Confirmed via Windows Task Manager → Performance → CPU, which displays "Виртуализация: Включено" (Virtualization: Enabled).

  1. PowerShell Verification

Running the following command in Admin PowerShell:
Get-ComputerInfo | Select-Object HyperVisorPresent, HyperVRequirementVMMonitorModeExtensions, HyperVRequirementVirtualizationFirmwareEnabled
Result: HyperVisorPresent: True — confirming the hypervisor is active at the OS level.

  1. Clean Reinstall of Claude Desktop

Performed a complete clean reinstall: uninstalled the app, deleted %APPDATA%\Claude directory, and installed a fresh download from claude.com/download. The Cowork tab now appears, but still shows the virtualization error.
Log Evidence
The log file at %APPDATA%\Claude\logs\cowork_vm_node.log consistently shows the following errors:
[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
These errors have been present since the initial installation on February 10, 2026, and persist through today (February 21, 2026) across multiple reinstalls and system restarts.
Current State
• Cowork tab IS visible in the Claude Desktop app (after clean reinstall with virtualization features enabled)
• Cowork displays 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."
• The Chat and Code tabs work perfectly
• All virtualization prerequisites are confirmed enabled at hardware, OS, and software levels

Related GitHub Issues
This appears to be the same or related issue reported by multiple users:
• GitHub Issue #25136 — yukonSilver marked as unsupported on Windows 11 Pro x64
• GitHub Issue #25142 — Cowork tab does not show up on Windows 11
• GitHub Issue #25692 — Cowork tab not appearing on Windows
• GitHub Issue #26090 — Cowork tab not showing on Windows 10 Home

Despite all virtualization features being correctly enabled, Cowork still shows "Virtualization is not enabled" and the VM is marked as unsupported. This appears to be a detection bug — the system meets all requirements but yukonSilver incorrectly classifies it as unsupported.

TheTeacherDude · 4 months ago

Cowork: yukonSilver marked as unsupported on Windows 11 Pro x64 — VM not supported (win32/x64)
Environment:

OS: Windows 11 Pro, Version 24H2, Build 26100.4946
Architecture: x64
Claude Desktop: v1.1.3918.0 (MSIX install from claude.com/download)
Install type: WindowsApps (MSIX package)

Virtualization status (all confirmed enabled):

CPU Virtualization: Enabled (confirmed in Task Manager)
Hyper-V: Enabled
Virtual Machine Platform: Enabled
Windows Hypervisor Platform: Enabled
bcdedit /enum shows: hypervisorlaunchtype Auto
Get-Service | findstr -i cowork shows: Running CoworkVMService Claude

What's wrong:
Cowork tab shows "Virtualization is not enabled" despite all virtualization features being fully enabled and confirmed working. CoworkVMService is running but the VM never starts.
Log output from cowork_vm_node.log:
2026-02-21 07:23:55 [info] [cleanupVMBundleIfUnsupported] yukonSilver not supported (status=unsupported), checking for stale bundle...
2026-02-21 07:28:39 [warn] [startVM] VM not supported (win32/x64), skipping
Steps taken that did not resolve the issue:

Verified CPU virtualization enabled in BIOS
Verified Hyper-V, Virtual Machine Platform, and Windows Hypervisor Platform all enabled in Windows Features
Ran Claude Desktop as Administrator
Full uninstall, deleted MSIX package data, clean reinstall
Rebooted multiple times

Expected behavior: Cowork should detect that hardware virtualization is fully enabled, download the VM bundle, and allow access to the Cowork workspace.
Actual behavior: yukonSilver VM configuration is marked as unsupported on a fully capable x64 Windows 11 Pro system, preventing the VM bundle from downloading and the Cowork tab from functioning.

usenkov · 4 months ago

System Information
Operating System: Windows 11 Pro x64
CPU: Intel Core(TM) i7-10870H @ 2.20GHz (8 cores, 16 threads)
RAM: 64 GB
Claude Desktop Version: Latest (downloaded February 21, 2026 from claude.com/download)
Subscription: Claude Pro

Steps Taken and Verification
I have systematically enabled and verified all virtualization prerequisites:

  1. Windows Features Enabled

All three required features have been enabled via optionalfeatures (Turn Windows features on or off):
• Hyper-V (including Hyper-V Platform and Hyper-V Management Tools) — Enabled ✅
• Virtual Machine Platform (Платформа виртуальной машины) — Enabled ✅
• Windows Hypervisor Platform — Enabled ✅

System was restarted after enabling these features.

  1. BIOS/UEFI Hardware Virtualization

Intel VT-x is enabled in BIOS. Confirmed via Windows Task Manager → Performance → CPU, which displays "Виртуализация: Включено" (Virtualization: Enabled).

  1. PowerShell Verification

Running the following command in Admin PowerShell:
Get-ComputerInfo | Select-Object HyperVisorPresent, HyperVRequirementVMMonitorModeExtensions, HyperVRequirementVirtualizationFirmwareEnabled
Result: HyperVisorPresent: True — confirming the hypervisor is active at the OS level.

  1. Clean Reinstall of Claude Desktop

Performed a complete clean reinstall: uninstalled the app, deleted %APPDATA%\Claude directory, and installed a fresh download from claude.com/download. The Cowork tab now appears, but still shows the virtualization error.
Log Evidence
The log file at %APPDATA%\Claude\logs\cowork_vm_node.log consistently shows the following errors:
[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
These errors have been present since the initial installation on February 10, 2026, and persist through today (February 21, 2026) across multiple reinstalls and system restarts.
Current State
• Cowork tab IS visible in the Claude Desktop app (after clean reinstall with virtualization features enabled)
• Cowork displays 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."
• The Chat and Code tabs work perfectly
• All virtualization prerequisites are confirmed enabled at hardware, OS, and software levels

Despite all virtualization features being correctly enabled, Cowork still shows "Virtualization is not enabled" and the VM is marked as unsupported. This appears to be a detection bug — the system meets all requirements but yukonSilver incorrectly classifies it as unsupported.

Rocco-alt · 4 months ago

Exact same issue

2026-02-21 10:45:05 [warn] [startVM] VM not supported (win32/x64), skipping
2026-02-21 10:58:58 [info] [cleanupVMBundleIfUnsupported] yukonSilver not supported (status=unsupported), checking for stale bundle...

m2f0 · 4 months ago

Environment:

OS: Windows 11 Pro, Version 25H2, Build 26200.7840
CPU: Intel Core i7-1360P (13th Gen)
RAM: 16GB
Claude Desktop: latest version (reinstalled clean)

Confirmed enabled:

Intel VT-x (BIOS): ✅
Hyper-V (Microsoft-Hyper-V): ✅ Enabled
Virtual Machine Platform: ✅ Enabled
Windows Sandbox (Containers-DisposableClientVM): ✅ Enabled
Virtualization shown as "Enabled" in Task Manager

Log from %APPDATA%\Claude\logs\cowork_vm_node.log:
[warn] [startVM] VM not supported (win32/x64), skipping
[info] [cleanupVMBundleIfUnsupported] yukonSilver not supported (status=unsupported), checking for stale bundle...
Steps tried:

Enabled all virtualization features via Windows Features
Ran bcdedit /set hypervisorlaunchtype auto
Full clean reinstall (deleted %APPDATA%\Claude and %LOCALAPPDATA%\Claude, restarted, fresh install)
sc query CoworkVMService returns nothing — service was never created

Result: Cowork tab shows "Virtualization is not enabled" despite all prerequisites being met. The root cause appears to be the yukonSilver not supported (status=unsupported) detection incorrectly flagging Windows 11 Pro x64 as unsupported.

deepakdarryani · 4 months ago

2026-02-21 21:56:50 [info] [cleanupVMBundleIfUnsupported] yukonSilver not supported (status=unsupported), checking for stale bundle...
same issue... Please help

Mdelacruzmelo · 4 months ago

Exact same issue https://github.com/anthropics/claude-code/issues/25136#issuecomment-3939015468
Please help

alex-vidaurre · 4 months ago

---

Device: HP Envy x360 (win32/x64)
OS: Windows 11 Pro (upgraded from Home specifically to meet Hyper-V requirements)
Claude Desktop version: latest

Problem:
Cowork fails to start despite all virtualization requirements being met. The logs show yukonSilver not supported (status=unsupported) and VM not supported (win32/x64), skipping repeatedly.

Verified working:

  • VT enabled in BIOS ✅
  • Hyper-V enabled in Windows (State: Enabled) ✅
  • Hypervisor active — systeminfo shows "A hypervisor has been detected" ✅

Log output (cowork_vm_node.log):

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

This appears to be the same root cause described in #25136. The hardware detection logic is incorrectly marking a fully capable machine as unsupported. Upgrading to Windows Pro did not resolve the issue.

---

4DTraveller · 4 months ago

Still broken on v1.1.3963 (Feb 22, 2026)
Windows 11 Pro Build 26100.7840, Hyper-V enabled, Pro plan, Canada
Same error after 5 updates: yukonSilver unsupported, VM not supported (win32/x64)
Tested versions: 2685 → 3363 → 3541 → 3963, all fail identically

jensolafkoch · 4 months ago

@4DTraveller

I had to completely uninstall and re-install (and probably reboot then) - 1.1.3963 does work now.

4DTraveller · 4 months ago
@4DTraveller I had to completely uninstall and re-install (and probably reboot then) - 1.1.3963 does work now.

Thanks, complete uninstall and re-install worked!

Jetliu-AEI · 4 months ago

1.1.4328 with Windows 11 pro Insider Preview Build 26200. Doesn't work.
Who can help? Many thanks!

praxxo · 4 months ago

### Same issue here — Build 26200, yukonSilver marked unsupported

Environment:

Windows 11 Pro 25H2 (OS Build 26200.7840)
x64, Hyper-V enabled and running
Claude Desktop latest (reinstalled fresh)
Max plan subscriber
CoworkVMService is present and running

Symptoms:

Cowork tab does not appear — only Chat and Code visible
systeminfo reports: "A hypervisor has been detected. Features required for Hyper-V will not be displayed"
This is a physical machine (not a VM)

Log output
(%APPDATA%\Claude\logs\cowork_vm_node.log):
[info] [cleanupVMBundleIfUnsupported] yukonSilver not supported (status=unsupported), checking for stale bundle...
[warn] [startVM] VM not supported (win32/x64), skipping
[error] [Callbacks] Swift VM addon not available for callbacks
This pattern repeats on every app launch since Feb 23. The VM never attempts to boot — the platform check rejects it before initialization.
Reinstalling the app does not resolve the issue. Awaiting a fix in the platform detection logic for Build 26200.

peterogilviebox · 4 months ago

Been going around in circles - the response I got from doing some testing and diagnosing

"The log confirms exactly what we suspected. The key lines are:
yukonSilver not supported (status=unsupported)
VM not supported (win32/x64), skipping
Swift VM addon not available for callbacks
This is Anthropic's bug, not yours. Claude Desktop is incorrectly classifying your perfectly capable Windows 11 Pro x64 system as unsupported. Your hardware is fine — it's a flaw in Cowork's platform detection logic.
This is a known bug reported by many others with identical setups to yours. There's nothing more you can do on your end to fix it — no settings to change, no workarounds that reliably solve it.
What I'd recommend now:

Report it directly to Anthropic at support.claude.ai — include the fact that your log shows yukonSilver not supported (status=unsupported) on Windows 11 Pro x64 with a paid plan. The more people who report it, the higher priority it gets.
File or upvote the GitHub issue at github.com/anthropics/claude-code/issues/25136 — that's the exact bug affecting you. Adding a comment with your specs (Windows 11 Pro 64-bit, non-ARM) helps Anthropic see the scale of the problem.
Keep Claude Desktop updated — Anthropic are actively pushing fixes, and this detection bug is on their radar.

I'm sorry it's not a more satisfying answer, Peter — you've done everything right and the problem is squarely on Anthropic's side."

github-actions[bot] · 4 months ago

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.