[BUG] Missing HCS services: vfpext - Cowork not working on Windows 11 Pro
Status Open
Maintainer reply None cached
Workaround ✓ Mentioned in thread ↓
Activity 85 comments · opened Jul 6, 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?
OS: Windows 11 Pro (Build 22621)
Claude Desktop version: latest
Issue: Cowork tab shows "Missing HCS services: vfpext" and cannot be clicked.
Steps taken:
- Hyper-V is enabled
- Ran: Enable-WindowsOptionalFeature -Online -FeatureName Microsoft-Hyper-V-All
- Ran: dism /online /enable-feature /featurename:Microsoft-Hyper-V /all /norestart
- Restarted multiple times
- Clean reinstalled Claude Desktop twice
Result: Still showing "Missing HCS services: vfpext", Cowork remains disabled.
<img width="303" height="151" alt="Image" src="https://github.com/user-attachments/assets/15043d3a-8fc9-4e2a-a6d2-ccf44fb58f48" />
What Should Happen?
Cowork tab should be clickable and launch the workspace successfully
Error Messages/Logs
Missing HCS services: vfpextSteps to Reproduce
Xóa hết nội dung mẫu đó đi, điền vào:
1. Open Claude Desktop on Windows 11 Pro
2. Click on Cowork tab
3. Tooltip shows "Missing HCS services: vfpext"
4. Cowork tab is disabled and cannot be clickedClaude Model
None
Is this a regression?
Yes, this worked in a previous version
Last Working Version
_No response_
Claude Code Version
1.18286.0.0
Platform
Anthropic API
Operating System
Windows
Terminal/Shell
Terminal.app (macOS)
Additional Information
_No response_
85 Comments
I'm experiencing the exact same issue on Windows 11 Pro. I enabled Hyper-V, created a virtual switch (Internal and External), confirmed vmms/vmcompute/hns are all Running, and vfpext.sys driver exists — but Cowork still shows "Missing HCS services: vfpext"
<img width="316" height="128" alt="Image" src="https://github.com/user-attachments/assets/dc18787c-1797-4c62-a568-f5e9382ba44d" />
Like others, I'm experiencing the exact same issue on Windows 11 Pro. OS Build 26200.8655
I enabled Hyper-V, did the virtual switch (Internal and External), confirmed vmms/vmcompute/hns and vfpext.sys driver exists — but Cowork still shows "Missing HCS services: vfpext"
Hitting this exact issue on a fresh setup — same "Missing HCS services: vfpext" tooltip, Cowork tab greyed out.
System: Windows 11 Pro, version 25H2, build 26200 (upgraded from Windows 11 Home specifically to get Cowork). Claude Desktop v1.19367.0, installed fresh with the current installer.
What I tried (all unsuccessful, same as OP):
Enable-WindowsOptionalFeature -Online -FeatureName Microsoft-Hyper-V -All→ enabledvmms/vmcompute/HNS(all confirmedRunning), butvfpext.sysnever appeared.Enable-WindowsOptionalFeature -Online -FeatureName Microsoft-Hyper-V-All -All(the full meta-feature, not just the parent) → same result,RestartNeeded: False, novfpext.sys.DISM /Online /Cleanup-Image /RestoreHealth— completed successfully (ruling out component-store corruption as the cause) —vfpext.sysstill absent afterward.Additional diagnostics that might help narrow this down:
vfpext.sysis missing not just fromSystem32\drivers, but also from the DriverStore (System32\DriverStore\FileRepository) entirely — it's not staged anywhere on the system, even after the DISM repair pulled fresh files from Windows Update.Get-VMSystemSwitchExtensionreturns nothing referencingvfp.CoworkVMServiceisRunningwithStartType: Automaticon my machine, so that's not a factor here (ruling out the separate "Manual startup" issue mentioned elsewhere).This suggests the Hyper-V Virtual Switch Forwarding Extension driver isn't being deployed by the standard
Microsoft-Hyper-V-Allfeature in some Windows 11 25H2 configurations, and/or Cowork's own installer/setup may need to provision or check for it directly rather than assuming the Windows feature toggle covers it. Happy to run further diagnostics if useful.Additional data point — Windows 11 Enterprise, confirmed driver missing from install media
Hitting the same issue on Windows 11 Enterprise (personal machine, not domain-managed). Additional troubleshooting details that may help narrow this down:
Get-WindowsOptionalFeature -Online -FeatureName Microsoft-Hyper-V-All → Enabled
All Hyper-V sub-features (Microsoft-Hyper-V, Microsoft-Hyper-V-Tools-All, Microsoft-Hyper-V-Management-PowerShell, Microsoft-Hyper-V-Hypervisor, Microsoft-Hyper-V-Services, Microsoft-Hyper-V-Management-Clients) → all Enabled
C:\Windows\System32\drivers\vfpext.sys → does not exist
Ran DISM /Online /Enable-Feature /FeatureName:Microsoft-Hyper-V /All /Source:E:\sources\sxs /LimitAccess against a fresh Windows 11 multi-edition consumer ISO — completed successfully, but CBS.log shows no reference to vfpext at all
Confirmed via Get-ChildItem -Recurse -Filter "vfpext.sys" against the mounted ISO itself — the driver is not present anywhere in the consumer multi-edition ISO
Ruled out pending reboot (RebootPending key = False) and Fast Startup interference (full cold shutdown/boot performed)
This suggests vfpext.sys may not ship in the consumer Windows 11 install media the way it does in Server editions, even though the Hyper-V feature toggles report fully enabled. Wondering if Cowork's HCS check needs a fallback path, or if there's a known alternate source for this driver on client SKUs.
Same here. Did some trials together with Claude, but didn't succeed:
System: Windows 11 Pro, Version 25H2, Build 26200.8737
Error: Cowork tab in Claude Desktop remains greyed out with the message "Missing HCS services: vfpext".
Steps already taken (without success):
Virtual Machine Platform: enabled and confirmed (State: Enabled)
Hyper-V (Microsoft-Hyper-V-All): enabled and confirmed (State: Enabled)
Windows Hypervisor Platform: enabled and confirmed (State: Enabled)
vfpext driver via Get-WindowsDriver -Online: not found
DISM /Online /Cleanup-Image /RestoreHealth: completed successfully
sfc /scannow: no integrity violations found
Performed multiple restarts and repeatedly enabled Hyper-V-All
Despite all this: Test-Path "C:\Windows\System32\drivers\vfpext.sys" still returns False, or the error persists
Hypothesis: The vfpext driver (Virtual Filtering Platform, part of the Hyper-V switch) is not being installed on this system despite the Windows features being fully enabled.
Edit: This workaround helped:
wsl --update
wsl --shutdown
Can also be used, if an update from Windows creates the same problems. Thanks for sharing your solutions!
Same issue as reported. Windows 11 Pro, Beelink mini PC. Symptom: Cowork shows "Missing HCS services: vfpext" and only appears as a small button (not a full sidebar tab).
Troubleshooting done: Enabled full Hyper-V via Enable-WindowsOptionalFeature, confirmed via Get-WindowsOptionalFeature -Online -FeatureName Hyper that Microsoft-Hyper-V-All, -Services, -Hypervisor, -Tools-All, -Management-PowerShell are all "Enabled". systeminfo confirms hypervisor is detected and running. Ran full DISM /RestoreHealth and Windows repair install from official Microsoft ISO (in-place upgrade, kept files/apps) — vfpext.sys and VfpExt.mof are still missing from disk after all of this (Test-Path returns False, Get-ChildItem returns nothing). Edition confirmed as genuine Professional via dism /online /get-currentedition.
This suggests Cowork's detection logic may be checking for something that isn't actually required, or there's a deployment gap specific to certain Windows 11 Pro OEM images (in my case, a Beelink mini PC with likely a customized factory image). Happy to provide more diagnostic output if useful.
Same issue here: Cowork fails to start with "Missing HCS services: vfpext" on Windows 11 Pro.
Environment:
What I tried (none fixed it):
Key finding: the vfpext service is not even registered on the system. Running
Get-Service vfpextin PowerShell returns:"Cannot find any service with service name 'vfpext'."
This happens even though Hyper-V shows as fully installed on Windows 11 Pro, and persists after reinstalling the Hyper-V feature.
Cowork tab shows the "Missing HCS services: vfpext" error and cannot be used. Regular Chat mode works fine. This looks specific to the 25H2 build. Happy to provide logs (cowork_vm_node.log / main.log) if helpful.
Sorry for my English, I'm French — I had the same issue this morning with VfpExt, and I fixed it with an update:
OS: Windows 11 Pro, version 25H2 (OS build 26200.8737)
After that, a restart my computer fixed it for me.
Experiencing the same issue, tried all the possible approach having claude code fixing my laptop and still unsuccess.
Looking forward to a solutions very soon
Same issue on my machine:
OS: Windows 11 Pro (Build 26100.1742)
Claude Desktop: latest
sc query vfpext returns no output (service does not exist)
bcdedit /enum | findstr -i hypervisorlaunchtype returns auto
Hyper-V is enabled in Windows Features
Toggling Hyper-V off/on did not fix
Enable-WindowsOptionalFeature -Online -FeatureName Microsoft-Hyper-V -All did not fix
Cowork tab shows "Missing HCS services: vfpext" and is disabled
Please prioritize a fix for this.
Like others, I'm experiencing the exact same issue on Windows 11 Pro.
yes Window 11 pro
This worked for me, thank you @guigui76300-lgtm
It is necessary for it to function.
<img width="447" height="111" alt="Image" src="https://github.com/user-attachments/assets/2c358d83-74eb-479d-953b-ada4c4f686a3" />
Cowork working now
Same issue. Even though I had virtualization enabled, I ran the following command via PowerShell, then rebooted. Issue resolved.
Enable-WindowsOptionalFeature -Online -FeatureName VirtualMachinePlatform -All -NoRestart
this worked for me too, thanks for sharing
Worked for me too, thanks for sharing!
Same issue.
OS: Windows 11 Pro (Build 22621)
Claude Desktop version: latest
Issue: Cowork tab shows "Missing HCS services: vfpext" and cannot be clicked.
En Windows 11 Pro 23H2 use los comandos:
Enable-WindowsOptionalFeature -Online -FeatureName VirtualMachinePlatform -All -NoRestart
Enable-WindowsOptionalFeature -Online -FeatureName Microsoft-Hyper-V -All
Y despues de reiniciar, cowork funcionó sin problemas. Espero les sirva tambien.
Thanks @guigui76300-lgtm this worked for me, too. Windows 11 Home, Version 25H2 (OS Build 26200.8655).
Thanks for reaching out! I’m on the most recent version of Windows 11 Pro, so not quite sure what the issue is. Hope anthropic fixes it soon so I can use Claude Cowork on my computer. Right now I only have access to “Claude Chat” and “Claude Code”.
Regards,
Darrel L. Longest, Esq.
MD Bar Only
@.****@.**>
(301) 252-3498
From: sonjathegrey @.*>
Sent: Wednesday, July 8, 2026 2:33 PM
To: anthropics/claude-code @.*>
Cc: Darrel L. Longest @.>; Comment @.>
Subject: Re: [anthropics/claude-code] [BUG] Missing HCS services: vfpext - Cowork not working on Windows 11 Pro (Issue #74649)
[Image removed by sender.]sonjathegrey left a comment (anthropics/claude-code#74649)<https://github.com/anthropics/claude-code/issues/74649#issuecomment-4918052330>
Sorry for my English, I'm French — I had the same issue this morning with VfpExt, and I fixed it with an update:
OS: Windows 11 Pro, version 25H2 (OS build 26200.8737)
wsl --update
wsl --shutdown
After that, a restart my computer fixed it for me.
Sorry for my English, I'm French — I had the same issue this morning with VfpExt, and I fixed it with an update:
OS: Windows 11 Pro, version 25H2 (OS build 26200.8737)
wsl --update
wsl --shutdown
After that, a restart my computer fixed it for me.
Thanks @guigui76300-lgtm<https://github.com/guigui76300-lgtm> this worked for me, too. Windows 11 Home, Version 25H2 (OS Build 26200.8655).
—
Reply to this email directly, view it on GitHub<https://github.com/anthropics/claude-code/issues/74649?email_source=notifications&email_token=CHZDSRAMTKYLLEBZNCKSPND5D2HVNA5CNFSNUABFM5UWIORPF5TWS5BNNB2WEL2JONZXKZKDN5WW2ZLOOQXTIOJRHAYDKMRTGMYKM4TFMFZW63VHMNXW23LFNZ2KKZLWMVXHJLDGN5XXIZLSL5RWY2LDNM#issuecomment-4918052330>, or unsubscribe<https://github.com/notifications/unsubscribe-auth/CHZDSRGJ2KJPFF5KCMKNSQD5D2HVNAVCNFSNUABFKJSXA33TNF2G64TZHM4TGNZSGUZTINZVHNEXG43VMU5TIOBRGU2TMMBZHE2KC5QC>.
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This worked for me as well. Thanks!!
I'm hitting this exact same issue.
Environment:
Steps to reproduce:
Adding my case to increase visibility — same blocking behavior as reported above. Let me know if there's any diagnostic info I can provide to help debug this.
Same issue on Windows 11 Pro 25H2 (Build 26200.8457). Fixed it.
The
vfpextdriver is registered by the Containers optional feature, not by Hyper-V. Enabling Hyper-V alone doesn't help.Check:
If
Disabled, run in an elevated PowerShell and reboot:After the reboot the Cowork tab is clickable and the VM boots normally.
Note: #37068 reports Containers causing an HCS 0x800701c0 failure on 25H2 + MSIX. I didn't hit that, but worth knowing.
Confirming the fix from @Edo771977 worked for me too.
Environment: Windows 11 Pro 25H2 (build 26200.8737), Lenovo ThinkPad E16 Gen 1
Error:
Missing HCS services: HNS, vmcompute, vfpextI went pretty deep trying to fix this before finding the right answer, so leaving a note in case it saves someone else the time. None of the following fixed it, even though they all completed "successfully":
Microsoft-Hyper-V-AllDISM /Online /Cleanup-Image /RestoreHealth(both WU-sourced and with an explicit/Source:pointing at an official Windows 11 ISO)sfc /scannowvfpext.sysfrom the WinSxS store intoSystem32\drivers(file existed there, correctly signed, but had no registered Windows service)vfpext.syswas staged in WinSxS (soGet-ChildItemwould find it) but had no service registry key atHKLM\SYSTEM\CurrentControlSet\Services\vfpext, andGet-WindowsPackage -Onlineshowed zero Hyper-V packages at all — the servicing stack wasn't tracking it.What actually fixed it:
After reboot,
vfpext.syswas present, thevfpextservice was registered (Stopped/Systemstart type, which is normal — it loads on demand), and Cowork worked immediately.Containersisn't part of the standard Hyper-V enablement checklist and isn't enabled by default on most machines, so this is easy to miss — the error message doesn't mention it at all.I'm experiencing the exact same issue on Windows 11 Pro.
Steps I took (none resolved it):
Enabled Hyper-V via Enable-WindowsOptionalFeature -Online -FeatureName Microsoft-Hyper-V-All
Confirmed via Get-WindowsOptionalFeature -Online -FeatureName Microsoft-Hyper-V-All → State: Enabled
Created a new external virtual switch in Hyper-V Manager, bound to my Wi-Fi adapter (Intel Wireless-AC 9462)
Enabled the "Microsoft Windows Filtering Platform" extension on that switch
Restarted the computer multiple times
Result: Claude Desktop's Cowork tab still shows "Missing HCS services: vfpext" and remains disabled.
This suggests the issue isn't a missing Windows feature/configuration on the user's end, but something in how Claude Desktop checks for or registers the vfpext service on Windows. Happy to provide more system details (build number, Claude Desktop version) if it helps with troubleshooting.
I was experiencing the exact same issue on Windows 11 Pro.
What I tried first (didn't resolve it on its own):
Enabled Hyper-V via Enable-WindowsOptionalFeature -Online -FeatureName Microsoft-Hyper-V-All
Confirmed via Get-WindowsOptionalFeature -Online -FeatureName Microsoft-Hyper-V-All → State: Enabled
Created a new external virtual switch in Hyper-V Manager, bound to my Wi-Fi adapter
Enabled the "Microsoft Windows Filtering Platform" extension on that switch
Restarted the computer multiple times
Cowork still showed "Missing HCS services: vfpext"
What actually fixed it:
Running this in an elevated PowerShell, then restarting the computer:
powershellEnable-WindowsOptionalFeature -Online -FeatureName VirtualMachinePlatform -All -NoRestart
After the restart, the Cowork tab worked normally — no more "Missing HCS services: vfpext" error.
It seems Hyper-V alone isn't enough; the VirtualMachinePlatform feature (the one that also backs WSL2) needs to be enabled separately for the vfpext service to register properly. Might be worth having the Claude Desktop installer check for and enable this feature automatically on Windows, since it's not obvious from the error message alone.
Confirming this on a different Windows build — same symptom, so it's not build-specific.
Environment
Steps already tried
DISM /Online /Enable-Feature /FeatureName:Microsoft-Hyper-V /All→ completed successfullyDiagnostics
Get-Service vmcompute, hns→ both Runningsc.exe query vfpext→ error 1060 (service does not exist)Test-Path C:\Windows\System32\drivers\vfpext.sys→ FalseOn this build there is no standalone
vfpextdriver/service, yet the Cowork readiness check still requires it. vmcompute and hns are healthy, so the local VM stack itself is functional — the check forvfpextseems to be the blocker. Please consider relaxing the readiness check to not hard-requirevfpextwhen vmcompute + hns are Running.Same issue here when trying to enable Cowork:
"Missing HCS services: HNS, vmcompute, vfpext"
Environment
Claude Version: 1.19367.0 (1a5be1)
Same here.
Windows 11 Pro 25H2 26200.8457
Claude 1.20186.0 (d7731e) 2026-07-09T06:13:11.000Z
Works here after this steps below
Found a workaround (Windows 11 Pro 25H2, Build 26200.8655)
Root cause in my case: the
vfpextdriver (Virtual Filtering Platform, a Hyper-V vSwitch extension) was present but STOPPED — it only loads on demand when an HNS network is created. It also rejects manual start:sc.exe query vfpext→STATE: STOPPED,WIN32_EXIT_CODE: 1077sc.exe start vfpext→Access is denied(even in elevated PowerShell)Fix: force HNS network creation via WSL2:
wsl --install --no-distribution(elevated PowerShell)The WSL virtual network loads
vfpextat boot. Suggestion for the Cowork readiness check: a stoppedvfpexton a machine with no HNS networks is a normal state, not a missing service — maybe trigger the network creation instead of blocking.Reboot. After this,
hnsandvmcomputewere Running:But the tooltip changed to
Missing HCS services: vfpext— Cowork still disabled.2. Diagnose vfpext:
Output:
Driver file exists (
Test-Path C:\Windows\System32\drivers\vfpext.sys→ True), it's just not loaded.3. Manual start does NOT work — even in an elevated prompt:
This is expected: vSwitch extension drivers can't be started standalone; they load when HNS creates a virtual network.
4. The actual fix — force HNS network creation via WSL2 (elevated PowerShell):
(
--no-distributioninstalls only the WSL platform, no Linux distro — ~no disk cost)5. Reboot.
6. Verify and reopen Claude Desktop:
Cowork tab enabled, error gone. Persists across reboots (the WSL HNS network loads vfpext at boot).
Suggestion for the Anthropic team
A stopped
vfpexton a machine with no HNS networks is a normal state, not a missing service. The readiness check should either trigger HNS network creation itself or surface actionable guidance instead of a dead-end tooltip.wsl --update
wsl --shutdown
Restart-Computer
Worked for me after I did all the things that took hours, was fixed in like 2 minutes.
I had this exact issue (Missing HCS services: vfpext, Cowork tab disabled) on Windows 11 Pro. I tried nearly everything before finding a working fix — sharing the full path in case it helps others.
What I tried that did NOT fix it:
What actually fixed it, in order:
Get-ChildItem "$env:SystemRoot\WinSxSvfpext" -Directory
Copy-Item "C:\WINDOWS\WinSxS\amd64_microsoft-windows-hyper-v-vfpext_[your folder name]\vfpext.sys" -Destination "C:\WINDOWS\System32\drivers\vfpext.sys"
Copy-Item "C:\WINDOWS\WinSxS\amd64_microsoft-windows-hyper-v-vfpext_[your folder name]\vfpapi.dll" -Destination "C:\WINDOWS\System32\vfpapi.dll"
Copy-Item "C:\WINDOWS\WinSxS\amd64_microsoft-windows-hyper-v-vfpext_[your folder name]\vfpctrl.exe" -Destination "C:\WINDOWS\System32\vfpctrl.exe"
New-VMSwitch -Name "TempSwitch" -NetAdapterName "Ethernet" -AllowManagementOS $true
(Replace "Ethernet" with your actual network adapter name — check with
Get-NetAdapter)wsl.exe --update
After this, Cowork opened and worked successfully. Note that even after all this,
sc query vfpextstill returned nothing (no registered service), yet Cowork worked anyway — so whatever internal check Claude Desktop uses for this, it doesn't seem to rely purely on the Windows service registration status.Hope this saves someone else the hours I spent on this.
Additional info: Confirmed this is a Windows 11 Home limitation, not just a driver/registration issue
Diagnostics performed:
bcdedit /enum (admin) — ran successfully, no access issues after elevating properly
Searched C:\Windows\System32\drivers for vfpext.sys — file does not exist on disk
sc query vfpext — "The specified service does not exist as an installed service"
dism /online /get-featureinfo /featurename:Microsoft-Hyper-V — Error 0x800f080c: "Feature name Microsoft-Hyper-V is unknown"
winver — confirmed Windows 11 Home
Conclusion: Hyper-V and its components (including vfpext.sys) aren't present in the Windows 11 Home image at all — this isn't a case of Hyper-V being disabled or misconfigured, it's genuinely absent from Home edition. DISM doesn't even recognize the feature name because it's not in the image to query.
This suggests the "Missing HCS services: vfpext" error may affect all Windows 11 Home users, not just this reporter's specific setup, since Cowork's sandbox currently seems to require Hyper-V. Might be worth either surfacing a clearer error/edition-check in the app, or exploring a non-Hyper-V sandbox path for Home users, since there's no user-side fix available (short of upgrading to Pro).
wsl --update
wsl --shutdown
Restart-Computer
Worked for me after I did all the things that took hours, was fixed in like 2 minutes.
wsl --update
wsl --shutdown
This worked for me to!
私も頂いた情報より PowerShellを管理者で起動して
下記コマンドで問題解決できました。ありがとうございました。
wsl --update
wsl --shutdown
Restart-Computer
エラー解決のためのClaudeとやりとりしてましたが、問題解決の結果報告したら下記回答でした。
-----------------------------------------------------------------------------------------------
wsl --update でWSL2側のカーネルおよび関連コンポーネント(vfpextを含む仮想スイッチドライバ群)が更新・再展開され、それが今回のケースではvfpext.sysの欠落を解消する形になったのだと思われます。
DISM/SFCはOSコンポーネントストア側の修復であるのに対し、wsl --updateはWSL2専用の配布パッケージを直接更新する仕組みのため、今回のようにHyper-V機能自体はEnabledでもファイルが欠けているケースでは、こちらの方が的確に効いたのでしょう。
Confirming the
wsl --update+wsl --shutdown+ restart fix worked for me too.Environment: Windows 11 Pro 25H2, HP EliteBook 830 G5 — after an entire session of failed attempts (clean Windows reinstall, BIOS factory reset, Secure Boot/VBS disabling via the official Microsoft DG_Readiness tool, multiple Hyper-V feature reinstall cycles), vfpext.sys never deployed and the service never registered.
Ran:
wsl --update
wsl --shutdown
then restarted the PC. wsl --update pulled in VirtualMachinePlatform as a dependency. After reboot, vfpext service appeared and is Running (Microsoft Azure VFP Switch Filter). Cowork works now.
Credit to the commenters who suggested wsl --update — that's what actually fixed it, not any of the Windows/BIOS-level VBS or Hyper-V troubleshooting.
P.D: JxUxAxNxPC desde Argentina carajo!
Confirming the wsl --update + wsl --shutdown + restart fix worked for me too. Windows 11 Pro, had already tried enabling Hyper-V/VirtualMachinePlatform/Containers, DISM repair, sfc /scannow — none of that worked, only this fixed it.
I'm hitting the exact same error on a different machine (Windows 11 Pro, 25H2, Build 26100.8655) and did a deep investigation — sharing in case it helps narrow this down, since it turned out to be more specific than a simple "Hyper-V not enabled" issue.
Root cause found:
vfpext.sysin my WinSxS store is present with the correct expected size (554592 bytes) and passes hash verification against what DISM deploys, but it is not a valid PE executable — the first two bytes areDCinstead of the expectedMZDOS header signature. Attemptingsc.exe start vfpextfails with Error 193 (ERROR_BAD_EXE_FORMAT).Despite this, CBS reports the
Microsoft-Hyper-V-Servicesfeature asCbsInstallStateInstalled(state 7), so it's never re-deployed by any of the normal repair paths:DISM /RestoreHealthvia Windows Update — no changeDISM /StartComponentCleanup— no changeMicrosoft-Hyper-V-All— no changeDISM /RestoreHealth /Source:esd:...pointing directly at a clean ISO — no change, still deployed the same corrupted fileThis suggests Cowork's HCS check is correctly detecting a real problem, but the underlying cause (a corrupted servicing-store artifact that standard DISM/SFC/in-place-repair can't detect or fix because CBS believes it's already installed) is outside what typical Windows troubleshooting catches.
Would be good to know:
Happy to share CBS.log / DISM debug logs if useful for triage.
Same issue here on a different machine.
Environment:
Test-Path C:\Windows\System32\drivers\vfpext.sys→ Falsesc.exe qc vfpext→ Error 1060, "The specified service does not exist as an installed service"Steps already tried, no change:
Disable/Enable-WindowsOptionalFeature -FeatureName Microsoft-Hyper-V)DISM /Online /Cleanup-Image /RestoreHealth— found and repaired corrupted filessfc /scannow— found and repaired corrupted filesNew-VMSwitch -SwitchType Internal) to try to trigger vfpext registrationNone of the above registered the vfpext service. Cowork still shows "Missing HCS services: vfpext" on hover.
Happy to provide logs (CBS.log, event viewer) if that helps debugging.
Also hitting this exact issue.
Environment:
Confirmed Hyper-V, Virtual Machine Platform, and Windows Hypervisor Platform enabled. Get-Service vmms and vmcompute both show Running. BIOS virtualization confirmed enabled. Restarted twice. Fully uninstalled/reinstalled Claude Desktop. Signed out and back in. None of it resolved the "Missing HCS services: vfpext" tooltip — Cowork tab remains disabled.
Also hitting this exact issue.
Environment:
OS: Windows 11 Pro, Version 25H2, OS Build 26200.8655
Claude Desktop version: 1.20186.0.0 (confirmed latest via reinstall from claude.ai/download)
Claude plan: Pro
Confirmed Hyper-V, Virtual Machine Platform, and Windows Hypervisor Platform enabled. Get-Service vmms and vmcompute both show Running. BIOS virtualization confirmed enabled. Restarted twice. Fully uninstalled/reinstalled Claude Desktop. Signed out and back in. None of it resolved the "Missing HCS services: vfpext" tooltip — Cowork tab remains disabled.
Same issue: Cannot run Cowork
NB: I'm running Windows on a MacBook Pro under Parallels (ARM64 + Parallels)
OS Name Microsoft Windows 11 Pro
Version 10.0.26200 Build 26200
OS Build 26200.8655
System Model Parallels ARM Virtual Machine
System Type ARM64-based PC
system type, Parallels + Apple Silicon Mac
Error I get when trying to start Cowork: Missing HCS Services: HNS, vmcompute, vfpext
Same issue, additional data point: Windows 10 Pro (not 11).
Confirmed vmms, HNS, and vmcompute all present and running. vfpext service
absent. Ran Get-WindowsDriver -Online filtering on vfpext — returns nothing,
so the driver file itself is missing from the driver store, not just
disabled/unbound.
Steps taken, none resolved it:
Management-PowerShell all "Enabled")
adapter) to force vfpext binding — no effect
Enable-WindowsOptionalFeature Microsoft-Hyper-V -All, reboot — vfpext
still not present in driver store after full reinstall
Looks like the vfpext driver package isn't being deployed at all by the
Hyper-V feature install on this hardware/build combo, rather than a
config or corruption issue.
Installing windows subsystem for linux using the wsl --install command fixed this issue for me.
I hit this exact issue on Windows 11 Pro (upgraded from Home specifically to get Hyper-V) and did a fairly deep investigation. Sharing findings in case they help narrow down the root cause.
Environment: Windows 11 Pro, build 10.0.26200.8655 (25H2)
What I tried (all failed to produce
vfpext):Enable-WindowsOptionalFeature -Online -FeatureName Microsoft-Hyper-V -All) —vmms,HNS,vmcomputecome up and run fine;vfpextnever appears as a service.DISM /Online /Cleanup-Image /RestoreHealth, both against Windows Update and against a locally mounted Windows 11 25H2 ISO (/Source:D:\sources\install.wim /LimitAccess) — completed successfully, no corruption found.sfc /scannow— clean, no integrity violations.Disable-WindowsOptionalFeature -Remove+ reinstall of Hyper-V from the local ISO source — same result.New-VMSwitch -SwitchType Internal) to force the VFP extension to load/register — succeeded, butvfpextstill doesn't appear.Key finding:
vfpext.sysdoes not exist anywhere on the system — not inSystem32\drivers, not in the DriverStore, and (this is the interesting part) not even inside the official Windows 11 25H2 install media (install.wim) itself. Instead there's awnetvsc_vfpp.infinC:\Windows\INF, which looks like it may be a renamed/refactored VFP driver package in this build.This suggests Cowork's HCS dependency check may be looking for a service/driver literally named
vfpext, which no longer exists under that name on current Windows 11 25H2 builds — possibly a Microsoft-side rename that Cowork's check hasn't been updated for. Might be worth checking what HCS service names current WSL2/Hyper-V builds actually expose instead of assumingvfpext.Follow-up to my comment above — found the fix.
The missing piece wasn't Hyper-V itself, it was Windows Sandbox (
Containers-DisposableClientVM), which was stillDisabledeven after Hyper-V/VirtualMachinePlatform/Containers were all enabled:After enabling it and rebooting,
vfpextshowed up as a real service (Stopped,StartType: System— it starts on demand when a switch is created) and Cowork started working immediately.So the full fix for "Missing HCS services: vfpext" on Windows 11 Pro appears to be: enable Hyper-V and Windows Sandbox, not just Hyper-V. Might be worth adding Windows Sandbox to the documented prerequisites, since it's easy to miss — it's off by default even on Pro/Enterprise and isn't mentioned as a Cowork requirement anywhere I could find.
Thank you, zachazran!!!
Confirmed — Containers-DisposableClientVM was also disabled on my Windows 11 Pro system despite Hyper-V being fully healthy (HNS/vmcompute running, hypervisor active, virtual switch present, all Hyper-V features enabled). Enabling Windows Sandbox fixed it immediately.
+1, this worked for me too. Thank you zachazran.
Confirmed the Windows Sandbox (Containers-DisposableClientVM) fix worked for me too.
Was Disabled, enabled it, rebooted, and Cowork started working immediately. Thanks zachazran-socialai!
I am having the same problem with Windows 10 Pro,
vmms/hns confirmed running,
vfpext still missing after manually creating a Hyper-V virtual switch,
restart didn't fix it.
[update:]
The fix from @zachazran-socialai above worked 😃
Same for me.....
Here are the steps/checks i did - nothing worked:
Bug: Cowork blocked — "Missing HCS services: HNS, vmcompute, vfpext" despite fully configured Hyper-V
Environment:
OS: Windows 11 Pro (activated)
Claude Desktop: latest version
CPU virtualization (Intel VT-x): Enabled in BIOS/UEFI
Issue:
Cowork tab is disabled with tooltip "Missing HCS services: HNS, vmcompute, vfpext" and cannot be clicked.
Verification steps completed:
Get-WindowsOptionalFeature -Online -FeatureName Microsoft-Hyper-V-All → State: Enabled
Get-Service vmcompute, vmms, hns → all three services: Running
BIOS: Virtualization Technology → Enabled
Full system restart performed after enabling Hyper-V
Full restart of Claude Desktop app (process fully quit, not just window closed)
Confirmed latest Claude Desktop version installed
Expected behavior:
Cowork tab should detect the running HCS services and become available.
Actual behavior:
Error persists identically after all above steps. This matches issue #74649, filed with the same symptoms on Windows 11 Pro with correctly configured Hyper-V.
Additional note:
This appears to be a detection/timing bug in Claude Desktop's HCS service check rather than an actual missing-service condition on the host.
Thanks for the feedback zachazran but still not working.
I unfortunately can't get Sandbox activated as this requires me to enable nested virtualization for Windows 11 under Parallels.
When I go open the Parallels Control Center, go to Configuration > Hardware > CPU & Memory, and click Advanced. Set the Hypervisor to Parallels and check Enable nested, I can't enable it and I see a message: Nested virtualization is currently not supported for the Apple hypervisor and for macOS virtual machines hosted on both Intel Mac and Apple Silicon Mac.
Any suggestions would be appreciated.
Also hitting this on Windows 11 Pro. Same "Missing HCS services: vfpext" error, Cowork tab disabled/greyed out.
Claude Desktop version: Claude 1.20186.1 (df1d8a) 2026-07-10T21:55:12.000Z
Windows build: Version 25H2 (OS Build 26200.8655)
Confirmed Hyper-V, Virtual Machine Platform, and Hypervisor Platform were not and then I enabled all via optionalfeatures.exe
Hyper-V enabled plus restart did not resolve
Possibly a related but distinct issue — worth flagging in case it helps narrow things down.
I'm seeing the same "Missing HCS services: HNS, vmcompute, vfpext" error with the Cowork tab disabled/greyed out, but on Windows 11 Home Single Language (not Pro).
Claude Desktop version: 1.20186.1 (df1d8a)
Windows build: Version 25H2 (OS Build 26200.8737)
After checking, it looks like this is expected on my end — Hyper-V and Virtual Machine Platform aren't available on Windows Home editions at all (confirmed VirtualMachinePlatform shows as Disabled and can't be enabled; Microsoft-Hyper-V-All and Containers don't even appear as available features).
Since this seems to be a Home-edition limitation rather than a bug, it might be worth having Cowork detect this and show a clearer message (e.g. "Cowork requires Windows Pro or higher") instead of the generic "Missing HCS services" error, which looks identical to the Pro-edition bug others are reporting here.
Thank you very much! It worked!
I was preparing to do a clean windows installation this post saved my day.
Additional data point — same issue, more exhaustive troubleshooting
OS: Windows 11 Pro
Claude Desktop: latest
Confirmed vfpext is not just stopped but completely absent from the system (sc query vfpext returns nothing at all, not even a "service does not exist" error).
Troubleshooting steps taken, in order, with restarts between each:
dism.exe /online /enable-feature /featurename:Microsoft-Hyper-V /all /norestart → Get-WindowsOptionalFeature -Online -FeatureName Microsoft-Hyper-V-All confirms State: Enabled
dism.exe /online /enable-feature /featurename:VirtualMachinePlatform /all /norestart
dism.exe /online /enable-feature /featurename:Containers /all /norestart
dism.exe /online /enable-feature /featurename:Containers-DisposableClientVM /all /norestart (Windows Sandbox) → confirmed State: Enabled after reboot
After each of these, sc query vfpext still returns empty — no service registered.
Also hit Error: 0x800f0806 ("pending operations") when running dism /online /cleanup-image /startcomponentcleanup mid-troubleshooting; a full restart cleared that pending-operation lock, but did not resolve the underlying vfpext issue.
Summary: Hyper-V, Virtual Machine Platform, Containers, and Windows Sandbox are all enabled and confirmed via Get-WindowsOptionalFeature, yet the vfpext driver never gets installed. This looks like an installer/packaging gap rather than a feature-enablement issue on the user side.
Thanks, it worked here with those commands.
Hello all, I had Hyper V enabled, but not Windows Sandbox. I enabled it as per above, restarted and then was glad to have Cowork enabled. Thank you all.
Same issue here - I have a special setup:
Win 11 Pro 23H2
Build 22631.6199
Running virtualized on ESXi-6.7.0-Update3
Hardware Virtualization for VM is enabled
IOMMU for VM is enabled
Claude Desktop Version 1.20186.1 (df1d8a)
Troubleshooting steps I've tried so far:
Microsoft-Hyper-V-AllandMicrosoft-Hyper-V-Hypervisorboth showState: EnabledviaGet-WindowsOptionalFeaturesc query vfpextreturned nothing at all (empty output), andDriverquery | findstr /i vfpfound no matching driver - the service wasn't registered on the system at allNew-VMSwitch -Name "ExternalSwitch" -NetAdapterName "Ethernet0" -AllowManagementOS $true) to see if that would trigger the driver to load - it didn't.Get-VMSwitchExtensionshowed the "Microsoft Windows Filtering Platform" extension present butEnabled: FalseDisable-WindowsOptionalFeature -FeatureName Microsoft-Hyper-V-All→ reboot →Enable-WindowsOptionalFeature -FeatureName Microsoft-Hyper-V-All -All→ reboot)sc query vfpextstill returns nothing/empty - the vfpext service/driver is still not registeredGiven the ESXi nested virtualization layer here, I suspect the vfpext driver deployment might be getting skipped specifically in nested setups, but happy to run any additional diagnostics if it helps narrow this down.
I'm hitting the exact same issue: Cowork tab disabled, tooltip shows "Missing HCS services: vfpext".
System: Windows 11 Pro, Version 25H2, Build 26200.8655, x64 (refurbished laptop)
What I found while debugging:
HNS, vmcompute, HvHost, vmms services are all present and Running
Only vfpext (Virtual Filtering Platform extension driver) is missing
sc.exe query vfpext → error 1060, "service does not exist" (no registry entry at all)
%SystemRoot%\System32\drivers\vfpext.sys does not exist on disk (Test-Path = False)
Windows Features GUI shows Hyper-V fully enabled (Platform, Services, Hypervisor, Management Tools all checked)
Get-VMSwitchExtension on a manually created test switch shows no VFP extension listed at all (only WFP and NDIS Capture)
Things I tried that did NOT fix it:
Enable-WindowsOptionalFeature -Online -FeatureName Microsoft-Hyper-V -All + reboot
DISM /Online /Cleanup-Image /RestoreHealth
sfc /scannow
Manually creating a Hyper-V virtual switch (New-VMSwitch) to try to force-load the driver
A full in-place repair install of Windows 11 using the official Microsoft Media Creation Tool ISO (keep files/apps option) — vfpext.sys was still missing afterward
Checked for Group Policy/WSUS restrictions on Windows Update/servicing (HKLM:\SOFTWARE\Policies\Microsoft\Windows\Servicing and ...\WindowsUpdate) — both empty, no restrictions found
Checked dism.log for errors related to Hyper-V/vfp — none found
So this doesn't seem to be a simple "enable Hyper-V" configuration issue — the underlying driver file appears to be genuinely absent from the Windows servicing store on some systems, and even official Windows repair mechanisms don't restore it. This also isn't tied to one specific Windows build, since other reporters here are on build 22621 and I'm on 26200 (25H2) with the identical symptom.
Would appreciate any guidance from the Anthropic team on what Cowork's HCS preflight check actually expects here, since normal troubleshooting/repair paths haven't resolved it for anyone in this thread so far.
Environment
Issue
Cowork tab shows "Missing HCS services: vfpext" and remains disabled/unclickable, even after Hyper-V is fully enabled and the underlying Windows component-store corruption that was blocking Hyper-V installation has been resolved.
Steps to reproduce
DISM /Online /Cleanup-Image /RestoreHealth→ failed repeatedly with error 0x800f0915 ("The repair content could not be found anywhere"), even after:DISM /Online /Cleanup-Image /CheckHealthconfirmed: "The component store is repairable" (detected corruption, not fixed).setup.exefrom the matched-build ISO, "Keep personal files and apps").sfc /scannow→ "Windows Resource Protection did not find any integrity violations" (clean).What's been ruled out
sfc /scannowis clean.Further troubleshooting (post component-store repair)
``
PS> Test-Path "C:\Windows\System32\drivers\vfpext.sys"
False
PS> Get-Service vfpext -ErrorAction SilentlyContinue
(no output — service not found)
The driver file is genuinely absent from disk, and no corresponding service is registered — this is not a stopped/misconfigured service, the component simply isn't present.
Additional notes
This matches other open reports of the same "Missing HCS services: vfpext" (and in some cases "HNS, vmcompute, vfpext") error on Windows 11 Pro. Notably, a separate Microsoft Q&A thread investigating what appears to be this exact issue for Claude Desktop's Cowork feature found the same result:
vfpext.sysmissing fromC:\Windows\System32\drivers, HNS and vmcompute running normally, and the file failing to reappear even afterDISM /RestoreHealth,sfc /scannow, disabling/re-enabling Hyper-V, and a full in-place repair install — all of which completed successfully without restoring the driver. Microsoft's assessment there was that this does not look like classic component-store corruption, but rather thatvfpext.sysmay no longer be deployed by default in the way expected on current Windows 11 25H2 builds, making this look like an application-compatibility gap rather than something fixable purely from the Windows side.Given that both a from-scratch Windows corruption repair and manual virtual switch creation failed to restore the driver on this machine, I'd consider the reasonable Windows-side troubleshooting path exhausted. This may need to be addressed on the Cowork/Claude Desktop side — either by not hard-depending on
vfpext.sysspecifically, detecting its absence and prompting a targeted fix, or documenting an alternate remediation for affected 25H2 systems.Happy to provide further logs (DISM.log, CBS.log,
Get-WindowsOptionalFeatureoutput) if useful.dism.log
I'm running into the same "Missing HCS services: HNS, vmcompute, vfpext" error described in this issue. Wanted to add my case since I went through several troubleshooting steps without success.
System: Windows 11 Pro, build 26200
Steps I tried:
Checked feature status with Get-WindowsOptionalFeature -Online — found Microsoft-Hyper-V-All and Containers disabled (VirtualMachinePlatform was already enabled)
Enabled them via Enable-WindowsOptionalFeature -Online -FeatureName Microsoft-Hyper-V-All -All, Containers, and Containers-HNS, then restarted
Confirmed after restart that all relevant features now show Enabled
Checked for the hns and vmcompute services with Get-Service — neither exists on the system
Checked for the vfpext driver with Get-WindowsDriver — not found
Tried repairing with DISM /Online /Cleanup-Image /RestoreHealth — failed (no internet source found for repair content)
Downloaded the official Windows 11 ISO and retried DISM using it as a source (/Source:D:\sources\install.esd) — failed with error 0x800f0915, "repair content could not be found"
The Cowork tab remains disabled with the same error even after all of the above. Happy to provide more logs/diagnostics if useful.
I hit this exact issue on Windows 11 Pro. Sharing my diagnostics and the fix that worked for me, in case it helps narrow down the root cause.
Symptom
systeminfoshowing "A hypervisor has been detected").Diagnostics
So the driver existed in the WinSxS component store but was never deployed to
System32\drivers, which meant thevfpextservice never got registered, even thoughMicrosoft-Hyper-V-AllandVirtualMachinePlatformboth reported as Enabled.Fix that worked
After reboot,
Get-Service vfpextreturned a valid (stopped/running) service,vfpext.syswas present underSystem32\drivers, and the Cowork tab became clickable again.Posting this in case others hitting the same "WinSxS has it, drivers folder doesn't" pattern find it useful. Happy to share more diagnostics if helpful.
Thanks to @gunmakko, I managed to fix the issue in my computer.
Here is my previous comment, updated with the full resolution steps.
------------------------------------------------------------------------------------
Environment
Issue
Cowork tab shows "Missing HCS services: vfpext" and remains disabled/unclickable, even after Hyper-V is fully enabled and the underlying Windows component-store corruption that was blocking Hyper-V installation has been resolved.
Steps to reproduce
DISM /Online /Cleanup-Image /RestoreHealth→ failed repeatedly with error 0x800f0915 ("The repair content could not be found anywhere"), even after:DISM /Online /Cleanup-Image /CheckHealthconfirmed: "The component store is repairable" (detected corruption, not fixed).setup.exefrom the matched-build ISO, "Keep personal files and apps").sfc /scannow→ "Windows Resource Protection did not find any integrity violations" (clean).What's been ruled out
sfc /scannowis clean.Further troubleshooting (post component-store repair)
``
PS> Test-Path "C:\Windows\System32\drivers\vfpext.sys"
False
PS> Get-Service vfpext -ErrorAction SilentlyContinue
(no output — service not found)
The driver file is genuinely absent from disk, and no corresponding service is registered — this is not a stopped/misconfigured service, the component simply isn't present.
Additional notes
This matches other open reports of the same "Missing HCS services: vfpext" (and in some cases "HNS, vmcompute, vfpext") error on Windows 11 Pro. Notably, a separate Microsoft Q&A thread investigating what appears to be this exact issue for Claude Desktop's Cowork feature found the same result:
vfpext.sysmissing fromC:\Windows\System32\drivers, HNS and vmcompute running normally, and the file failing to reappear even afterDISM /RestoreHealth,sfc /scannow, disabling/re-enabling Hyper-V, and a full in-place repair install — all of which completed successfully without restoring the driver. Microsoft's assessment there was that this does not look like classic component-store corruption, but rather thatvfpext.sysmay no longer be deployed by default in the way expected on current Windows 11 25H2 builds, making this look like an application-compatibility gap rather than something fixable purely from the Windows side.Given that both a from-scratch Windows corruption repair and manual virtual switch creation failed to restore the driver on this machine, I'd consider the reasonable Windows-side troubleshooting path exhausted. This may need to be addressed on the Cowork/Claude Desktop side — either by not hard-depending on
vfpext.sysspecifically, detecting its absence and prompting a targeted fix, or documenting an alternate remediation for affected 25H2 systems.Happy to provide further logs (DISM.log, CBS.log,
Get-WindowsOptionalFeatureoutput) if useful.Update — RESOLVED
Following up with the fix that worked — credit to @gunmakko, who hit the identical pattern and shared their diagnostics/fix in this thread.
Root cause confirmed: the
vfpextcomponent was present in the WinSxS component store but was never actually deployed toSystem32\drivers, even thoughMicrosoft-Hyper-V-AllandVirtualMachinePlatformboth reported as Enabled. Confirmed via:→ returned a matching folder (
amd64_microsoft-windows-hyper-v-vfpext_...), confirming the component was staged but not deployed.Fix that resolved it (run as Administrator; adjust the mounted ISO drive letter as needed):
Then restart.
Using
-Source D:\sources\sxspointing at a locally mounted Windows 11 25H2 ISO (rather than letting the command reach out to Windows Update) was important on this machine specifically, given the earlier Windows Update reachability issues encountered during the component-store repair.Post-reboot verification:
Cowork tab is now enabled and functional. Posting this in case the "WinSxS has it, drivers folder doesn't" pattern + full disable/re-enable of
VirtualMachinePlatform(ideally with a local ISO source) helps others hitting the same issue.<img width="932" height="588" alt="Image" src="https://github.com/user-attachments/assets/86f2740e-55c1-4741-a7a7-ca6eb5b45424" />
Environment: Windows 11 Pro, Build 26100.8521 (image version 10.0.26200.8655)
Diagnostics performed:
Conclusion: vfpext.sys exists in WinSxS (two versions found: 10.0.26100.7920 and 10.0.26100.8521) and on disk in System32\drivers, but is never bound to the Hyper-V extensible switch. This appears to be a Windows servicing/deployment bug, not an app-side issue.
Also hitting this on Windows 11 Pro (Build 26200), Lenovo 11BH001WAX, Intel Core i5-9400 CPU, 16GB RAM.
Confirmed CoworkVMService is running (checked via Get-Service), but the Cowork tab still shows "Missing HCS services: vfpext" and remains disabled.
Steps taken:
Verified CoworkVMService status — Running
Restarted Claude Desktop fully
Same result: Cowork tab disabled, tooltip shows "Missing HCS services: vfpext"
Windows 11 Pro, build 26200 (25H2), confirmed current via winver and Get-ComputerInfo. Same "Missing HCS services: vfpext" error persists after: full DISM /RestoreHealth, sfc /scannow (reported fixes), two full Hyper-V-All remove/reinstall cycles via DISM, and a complete in-place OS upgrade from 23H2→25H2.
Deeper diagnosis: Get-VMSwitchExtension -VMSwitchName * shows only "Microsoft Windows Filtering Platform" and "Microsoft NDIS Capture" registered — no VFP extension exists at all. pnputil /enum-drivers | findstr /i vfp returns zero results — the VFP driver package isn't staged in the driver store, despite HNS and vmcompute services running normally. This suggests the VFP component was never included in this machine's Windows installation image/manifest, which is why standard repair tools (DISM/SFC) report "healthy" — they only check integrity of what's supposed to be present, and VFP apparently isn't in that manifest for this build lineage.
Hitting this same issue on Windows 11, build 26200. Confirmed:
Get-WindowsOptionalFeature -Online -FeatureName Microsoft-Hyper-V-All → Enabled
Test-Path C:\Windows\System32\drivers\vfpext.sys → False
Directory:
C:\Windows\WinSxS\amd64_microsoft-windows-hyper-v-vfpext_31bf3856ad364e35_10.0.26100.8521_none_9c6e9b959bce5329
Mode LastWriteTime Length Name
---- ------------- ------ ----
-a---- 12/6/2026 6:31 PM 1671168 vfpext.sys
Directory:
C:\Windows\WinSxS\amd64_microsoft-windows-hyper-v-vfpext_31bf3856ad364e35_10.0.26100.8521_none_9c6e9b959bce5329\r
Mode LastWriteTime Length Name
---- ------------- ------ ----
-a---- 12/6/2026 6:31 PM 92087 vfpext.sys
main.log
cowork_vm_node.log
Tried: full disable/enable cycle of Hyper-V, DISM /RestoreHealth, sfc /scannow — none resolved it
Still shows "Missing HCS services: vfpext" in Claude Desktop
Turn on "Virtual Machine Platform" in Optional Features as well as Hyper-V & reboot. Seems to fix
johnnyitteam's suggestion is working like magic.
Same "Missing HCS services: vfpext" here, and I traced it to a component-store mismatch after upgrading to Windows 11 25H2. Sharing the full diagnosis in case it helps fix the detection/provisioning.
Environment
What I verified
Get-Service vmcompute, hns→ both RunningGet-Service vfpext→ service does not existGet-WindowsOptionalFeature -Online -FeatureName Microsoft-Hyper-V-All→ EnabledGet-WindowsOptionalFeature -Online -FeatureName Microsoft-Hyper-V-Hypervisor→ EnabledTest-Path C:\Windows\System32\drivers\vfpext.sys→ False (driver binary absent from disk)What did NOT fix it
DISM /Online /Cleanup-Image /RestoreHealth+sfc /scannow→ no change, vfpext.sys still absentDisable-WindowsOptionalFeature Microsoft-Hyper-V-All→ reboot → re-enable → reboot → still absentbcdedit /set hypervisorlaunchtype auto→ no effect (nothing to load, file missing)Root cause
The component store only holds vfpext.sys for 26100.xxxx (24H2) builds:
There is no 26200 (25H2) revision of vfpext in WinSxS on this machine, so Windows can't project the driver into
System32\drivers\. The 25H2 in-place upgrade appears not to have provisioned a 26200 vfpext into the store. This likely explains why Cowork's HCS check fails on freshly-upgraded 25H2 systems even though Hyper-V is fully enabled.Workaround that worked
Copied the closest revision (26100.8875, matching my UBR) from WinSxS, registered the service, forced the hypervisor, rebooted:
After reboot,
Get-Service vfpextresolves and the Cowork tab is enabled and working.Suggestion
This is a workaround, not a clean fix (a 26100 driver on a 26200 system). It would be worth: (1) having the Cowork preflight surface why vfpext is missing (feature enabled but binary absent vs. service not started), and (2) checking store provisioning of vfpext on 25H2/26200 upgrades, since that seems to be the underlying trigger.
worked after trying johnnyitteam's suggestion. Thank you
Hello guys,
To be totally frank and honest, I am in no way shape or form qualified to give any solutions or advice. My knowledge on coding is equivalent to a donkey's knowledge on quantum mechanics. However, I followed a series of steps and it worked for me.
The issues that I have shown up are the following: Missing HCS services: HNS, vmcompute,vfpext
Although I am not knowledgeable of code, one thing that I do best is follow instructions, so these are the EXACT steps that I have followed that allowed me to activate Claude Cowork for me:
Open PowerShell as Administrator and run:
Get-WindowsOptionalFeature -Online -FeatureName VirtualMachinePlatform
Get-Service vmcompute, hns
Enable-WindowsOptionalFeature -Online -FeatureName VirtualMachinePlatform -All
bcdedit
Check that hypervisorlaunchtype reads Auto. If not:
bcdedit /set hypervisorlaunchtype auto
Then restart
A couple of things worth checking first:
Windows edition matters — Home editions typically lack the Hyper-V/virtualization layer Cowork needs, so this only works reliably on Pro, Enterprise, or Education editions.
If you've already manually started vmcompute and hns and they show as "Running" but vfpext still can't be found, that's a sign the Hyper-V platform components themselves aren't fully installed (not just the services) — in that case, try re-enabling the Hyper-V feature itself alongside Virtual Machine Platform:
Enable-WindowsOptionalFeature -Online -FeatureName Microsoft-Hyper-V-All -All
then restart.
If none of this resolves it, this is a known reported issue, so it may be worth flagging to Anthropic support directly with your Windows edition/build info.
Why hasn’t Anthropic fixed or addressed this issue in the last two weeks? @claude
This worked for me! Thanks
Fixed it for me too after many reinstalls, cache clearing, MSIX powershell install, DISM etc - many thanks to the contributor of this advice!
Resolved on my machine: the missing feature was
Containers-SDNWindows 11 Pro 25H2, build 26200.8655, x64.
Every fix in this thread failed for me — Hyper-V enable/disable cycles, DISM
/RestoreHealth, sfc /scannow, and a full in-place repair upgrade from the
current ISO.
vfpext.sysstayed absent from System32\drivers throughout,though the payload was present in WinSxS the whole time.
The actual cause: Hyper-V was fully enabled, but the entire Containers/SDN
side was never on. VFP is the SDN data plane, so enabling Hyper-V alone
never deploys it.
Get-WindowsOptionalFeature -Online | Where-Object FeatureName -match'Hyper-V|Container|VirtualMachine|Hypervisor|Sandbox' | Select FeatureName, State
showed all Microsoft-Hyper-V-* as Enabled, while these were Disabled:
VirtualMachinePlatformContainersContainers-HNSContainers-SDNHypervisorPlatformFix (elevated PowerShell, then Restart — not Shutdown; Fast Startup can
skip driver staging):
After restart:
Test-Path C:\Windows\System32\drivers\vfpext.sys→Truesc.exe query vfpext→RUNNING(KERNEL_DRIVER)Microsoft Azure VFP Switch Filter Extensionnow appears underGet-VMSwitchExtension -VMSwitchName "Default Switch"Cowork then worked after clearing the cache via Help → Troubleshoot and
restarting the app.
Suggestion: the "Missing HCS services" error points people at Hyper-V,
which is misleading when Hyper-V is already fully enabled. Naming the
Containers/SDN features — or checking their state in the preflight — would
save a lot of time.
Salut !
Chez moi, sous Windows 11 Pro cela à aussi fonctionné.
Merci pour le tuyau !
Same symptom, and I want to add data since it doesn't match the causes already covered in this thread.
Setup: Windows 11 Pro, build 10.0.26200.8973. Worked previously with no changes made to Windows Update, drivers, or virtualization-related software in the intervening period (confirmed via file timestamps; no relevant updates in that window).
Confirmed reproducible behavior:
dism /online /enable-featureforMicrosoft-Hyper-V-All,VirtualMachinePlatform,Containers,Containers-HNS,Containers-SDN, andHypervisorPlatformall report success and showEnabled/Enable Pendingimmediately after. After a genuine restart (confirmed viaLastBootUpTime, fast startup and hibernation both disabled), all six silently revert toDisabled,vfpext.sysis missing fromSystem32\drivers, andHNS/vmcompute/vfpextdon't exist as services. Reproduced this exact cycle twice.Ruled out, with direct tests (not just checked settings):
vgk.sys): suspected this first since it's a known real-world Hyper-V conflict. Setvgktostart=disabled, confirmedSTOPPED/DISABLEDstate, re-ran the full enable + reboot cycle. Still reverted. Not the cause here (though worth others checking if they have similar anti-cheat installed).HiberbootEnabled=0,powercfg /hibernate off), real restart confirmed each time.gpresult /rshows only Local Group Policy, nothing restricting these features.wsl --update: applied (updated WSL to 2.7.11), didn't change the outcome.Component store:
DISM /CheckHealthand/ScanHealthboth report "repairable," butsfc /scannowfinds zero integrity violations, and/RestoreHealthfails with0x800f0915(repair source unreachable) regardless of network/VPN state, likely just no WU-hosted repair content for this build, not indicative of real corruption.So on this machine, the six-feature-enable fix that worked for others in this thread does not persist across reboot, and I can't find a local (Windows-side) cause after fairly exhaustive testing. Given it worked before with nothing relevant changing, my best guess is this is genuinely regressed on the Cowork/Claude Desktop side, not purely a local Windows config issue. Happy to run further diagnostics if anyone from Anthropic wants specific output.