[BUG] Missing HCS services: vfpext — persists after DISM, SFC, and full in-place Windows 11 reinstall
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?
Preflight Checklist
I have searched existing issues and this hasn't been reported yet (similar reports exist, e.g. #74649, #77277, #78866, #78858, but none confirm persistence after a full OS reinstall)
This is a single bug report
I am using the latest version of Claude Code
What's Wrong?
Claude Desktop's Cowork tab shows "Missing HCS services: vfpext" and remains disabled. The vfpext.sys driver file is missing from C:\Windows\System32\drivers, confirmed via Test-Path.
Environment
OS: Windows 11 Pro, x64
Claude Desktop: latest version at time of testing
Install method: standard installer with admin/UAC elevation accepted
Steps Taken (in order, each unsuccessful)
Enabled Hyper-V, Virtual Machine Platform, Windows Hypervisor Platform via Enable-WindowsOptionalFeature, rebooted — features report "Enabled" but vfpext.sys still absent.
Ran DISM /Online /Cleanup-Image /RestoreHealth (elevated) — completed successfully.
Ran sfc /scannow (elevated) — found and repaired unrelated corrupted files.
Rebooted, re-checked — vfpext.sys still absent.
Performed a full in-place Windows 11 reinstall via ISO (setup.exe, "Keep personal files" — downgraded to "personal files only" due to a language-mismatch prompt during setup), all apps/files otherwise preserved.
Post-reinstall, re-enabled Hyper-V and Virtual Machine Platform, rebooted.
Test-Path "C:\Windows\System32\drivers\vfpext.sys" still returns False.
Expected
vfpext.sys should be deployed to System32\drivers when Hyper-V/Virtual Machine Platform are enabled on a Windows 11 Pro x64 system, or a full OS reinstall should restore it if a prior deployment gap caused this.
Actual
The driver is not deployed under any of the above, despite Hyper-V and VMP reporting "Enabled" at the OS level. vmcompute and hns services were not individually verified as present/absent — only vfpext was confirmed missing at each stage.
Additional Notes
This matches the pattern reported in #78866 and #78858 (driver missing rather than merely unregistered) but adds that the issue survives a full in-place Windows reinstall, suggesting the deployment source itself (WinSxS component store or install media) may lack this driver for some system configurations, rather than it being a one-off servicing corruption.
What Should Happen?
Preflight Checklist
I have searched existing issues and this hasn't been reported yet (similar reports exist, e.g. #74649, #77277, #78866, #78858, but none confirm persistence after a full OS reinstall)
This is a single bug report
I am using the latest version of Claude Code
What's Wrong?
Claude Desktop's Cowork tab shows "Missing HCS services: vfpext" and remains disabled. The vfpext.sys driver file is missing from C:\Windows\System32\drivers, confirmed via Test-Path.
Environment
OS: Windows 11 Pro, x64
Claude Desktop: latest version at time of testing
Install method: standard installer with admin/UAC elevation accepted
Steps Taken (in order, each unsuccessful)
Enabled Hyper-V, Virtual Machine Platform, Windows Hypervisor Platform via Enable-WindowsOptionalFeature, rebooted — features report "Enabled" but vfpext.sys still absent.
Ran DISM /Online /Cleanup-Image /RestoreHealth (elevated) — completed successfully.
Ran sfc /scannow (elevated) — found and repaired unrelated corrupted files.
Rebooted, re-checked — vfpext.sys still absent.
Performed a full in-place Windows 11 reinstall via ISO (setup.exe, "Keep personal files" — downgraded to "personal files only" due to a language-mismatch prompt during setup), all apps/files otherwise preserved.
Post-reinstall, re-enabled Hyper-V and Virtual Machine Platform, rebooted.
Test-Path "C:\Windows\System32\drivers\vfpext.sys" still returns False.
Expected
vfpext.sys should be deployed to System32\drivers when Hyper-V/Virtual Machine Platform are enabled on a Windows 11 Pro x64 system, or a full OS reinstall should restore it if a prior deployment gap caused this.
Actual
The driver is not deployed under any of the above, despite Hyper-V and VMP reporting "Enabled" at the OS level. vmcompute and hns services were not individually verified as present/absent — only vfpext was confirmed missing at each stage.
Additional Notes
This matches the pattern reported in #78866 and #78858 (driver missing rather than merely unregistered) but adds that the issue survives a full in-place Windows reinstall, suggesting the deployment source itself (WinSxS component store or install media) may lack this driver for some system configurations, rather than it being a one-off servicing corruption.
Error Messages/Logs
Preflight Checklist
I have searched existing issues and this hasn't been reported yet (similar reports exist, e.g. #74649, #77277, #78866, #78858, but none confirm persistence after a full OS reinstall)
This is a single bug report
I am using the latest version of Claude Code
What's Wrong?
Claude Desktop's Cowork tab shows "Missing HCS services: vfpext" and remains disabled. The vfpext.sys driver file is missing from C:\Windows\System32\drivers, confirmed via Test-Path.
Environment
OS: Windows 11 Pro, x64
Claude Desktop: latest version at time of testing
Install method: standard installer with admin/UAC elevation accepted
Steps Taken (in order, each unsuccessful)
Enabled Hyper-V, Virtual Machine Platform, Windows Hypervisor Platform via Enable-WindowsOptionalFeature, rebooted — features report "Enabled" but vfpext.sys still absent.
Ran DISM /Online /Cleanup-Image /RestoreHealth (elevated) — completed successfully.
Ran sfc /scannow (elevated) — found and repaired unrelated corrupted files.
Rebooted, re-checked — vfpext.sys still absent.
Performed a full in-place Windows 11 reinstall via ISO (setup.exe, "Keep personal files" — downgraded to "personal files only" due to a language-mismatch prompt during setup), all apps/files otherwise preserved.
Post-reinstall, re-enabled Hyper-V and Virtual Machine Platform, rebooted.
Test-Path "C:\Windows\System32\drivers\vfpext.sys" still returns False.
Expected
vfpext.sys should be deployed to System32\drivers when Hyper-V/Virtual Machine Platform are enabled on a Windows 11 Pro x64 system, or a full OS reinstall should restore it if a prior deployment gap caused this.
Actual
The driver is not deployed under any of the above, despite Hyper-V and VMP reporting "Enabled" at the OS level. vmcompute and hns services were not individually verified as present/absent — only vfpext was confirmed missing at each stage.
Additional Notes
This matches the pattern reported in #78866 and #78858 (driver missing rather than merely unregistered) but adds that the issue survives a full in-place Windows reinstall, suggesting the deployment source itself (WinSxS component store or install media) may lack this driver for some system configurations, rather than it being a one-off servicing corruption.Steps to Reproduce
Preflight Checklist
I have searched existing issues and this hasn't been reported yet (similar reports exist, e.g. #74649, #77277, #78866, #78858, but none confirm persistence after a full OS reinstall)
This is a single bug report
I am using the latest version of Claude Code
What's Wrong?
Claude Desktop's Cowork tab shows "Missing HCS services: vfpext" and remains disabled. The vfpext.sys driver file is missing from C:\Windows\System32\drivers, confirmed via Test-Path.
Environment
OS: Windows 11 Pro, x64
Claude Desktop: latest version at time of testing
Install method: standard installer with admin/UAC elevation accepted
Steps Taken (in order, each unsuccessful)
Enabled Hyper-V, Virtual Machine Platform, Windows Hypervisor Platform via Enable-WindowsOptionalFeature, rebooted — features report "Enabled" but vfpext.sys still absent.
Ran DISM /Online /Cleanup-Image /RestoreHealth (elevated) — completed successfully.
Ran sfc /scannow (elevated) — found and repaired unrelated corrupted files.
Rebooted, re-checked — vfpext.sys still absent.
Performed a full in-place Windows 11 reinstall via ISO (setup.exe, "Keep personal files" — downgraded to "personal files only" due to a language-mismatch prompt during setup), all apps/files otherwise preserved.
Post-reinstall, re-enabled Hyper-V and Virtual Machine Platform, rebooted.
Test-Path "C:\Windows\System32\drivers\vfpext.sys" still returns False.
Expected
vfpext.sys should be deployed to System32\drivers when Hyper-V/Virtual Machine Platform are enabled on a Windows 11 Pro x64 system, or a full OS reinstall should restore it if a prior deployment gap caused this.
Actual
The driver is not deployed under any of the above, despite Hyper-V and VMP reporting "Enabled" at the OS level. vmcompute and hns services were not individually verified as present/absent — only vfpext was confirmed missing at each stage.
Additional Notes
This matches the pattern reported in #78866 and #78858 (driver missing rather than merely unregistered) but adds that the issue survives a full in-place Windows reinstall, suggesting the deployment source itself (WinSxS component store or install media) may lack this driver for some system configurations, rather than it being a one-off servicing corruption.
Claude Model
None
Is this a regression?
Yes, this worked in a previous version
Last Working Version
_No response_
Claude Code Version
1.0.123
Platform
Anthropic API
Operating System
Windows
Terminal/Shell
PowerShell
Additional Information
_No response_
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7 Comments
Windows 11 Pro, 버전 25H2, 빌드 26200.8875에서 동일 증상 확인됨.
sc.exe query vfpext → 1060 오류 (서비스 없음)
vfpext.sys 파일 자체가 없음 (Test-Path 결과 False)
DISM /RestoreHealth, sfc /scannow 둘 다 실행했지만 해결 안 됨.
"Missing HCS services: vfpext — persists after DISM, SFC, and full in-place Windows 11 reinstall") almost exactly. Since you've now also confirmed it survives a full disable/re-enable cycle, that's useful new data for that thread. Include:
Build: 26200.8875
CPU: AMD Ryzen 5 6600H
Confirmed: DISM RestoreHealth ran clean, SFC found and repaired corrupt files, vmcompute/hns running, Hyper-V-All fully re-deployed via disable/enable cycle — vfpext.sys still absent afterward
Title: Missing HCS services: vfpext — persists on Windows 11 Pro x64 (Surface, Snapdragon X Elite) after full Hyper-V enable and edition upgrade from Home
Environment:
What's wrong:
Cowork's "Missing HCS services" error persists even after a from-scratch Hyper-V enable and a full Windows edition upgrade (Home → Pro) performed specifically to fix it.
Steps taken, in order:
Diagnosis:
Hyper-V is fully enabled at the OS level, vmcompute and hns are confirmed Running, but the vfpext.sys driver is never deployed to System32\drivers despite the feature reporting Enabled and a full edition upgrade. This matches the pattern reported in #78866, #78858, and #80584 — the deployment step that stages this specific driver from the component store appears to be broken, independent of Windows edition (reproduced here on Pro, not just Home) and independent of CPU architecture (reproduced here on x64 Claude Desktop on ARM64 hardware, and #80584 reproduced it on x64 hardware entirely).
Expected behavior:
Either the vfpext driver deploys correctly once Hyper-V/VMP are enabled and confirmed Running, or Cowork's error message/documentation should clarify that this specific driver-deployment gap is a known, unresolved issue rather than presenting it as a standard "enable Hyper-V" fix that a full edition upgrade is expected to resolve.
Additional note: this issue cost a $99 Windows edition upgrade attempted specifically on the expectation that it would resolve the error, which it did not. Worth reflecting in documentation/support guidance so others don't spend money on the same assumption without a clearer risk disclosure.
I hit this exact issue on a fresh Windows 11 Pro install and fresh Claude Desktop install (latest versions). Tried both VMware and Hyper-V — same "Missing HCS services: vfpext" error with both.
Diagnosis:
This looks like a genuine detection bug on Cowork's side rather than anything fixable from the Windows/user side, since Default Switch is intentionally non-configurable by Microsoft design.
Same issue on my end — Windows 11 Pro (not ARM64, standard x64).
Confirmed vfpext.sys genuinely absent from disk, not just a detection false-negative like #80122:
PS> Test-Path C:\Windows\System32\drivers\vfpext.sys
False
vmcompute and hns are both present and running correctly — only vfpext is missing.
Already tried, no effect:
Disable/re-enable Microsoft-Hyper-V and VirtualMachinePlatform optional features (restart between each)
DISM /Online /Cleanup-Image /ScanHealth
DISM /Online /Cleanup-Image /RestoreHealth
sfc /scannow
Clearing Claude Desktop cache via Help → Troubleshoot (as suggested for #80122) — no change
Adding this as another data point that the deployment source (WinSxS/install media) may be missing this driver on some configurations, consistent with what you found after the full reinstall.
Same issue on Windows 11 x64 desktop (not ARM64), build 26200 / image 10.0.26200.8973.
vmcompute and hns both Running, but vfpext.sys was never projected from WinSxS into System32\drivers\, so sc.exe query vfpext returns 1060 and Cowork stays disabled.
Standard fixes did not work: DISM /Online /Cleanup-Image /RestoreHealth, disabling/re-enabling the Hyper-V feature, and multiple restarts.
What fixed it for me: manually copying the latest vfpext.sys from the WinSxS component store into the drivers folder, then rebooting:
powershell
$src = Get-ChildItem C:\Windows\WinSxS\ -Recurse -Filter vfpext.sys -ErrorAction SilentlyContinue |
Where-Object { $_.FullName -notlike '\r\' } |
Sort-Object LastWriteTime | Select-Object -Last 1
Copy-Item $src.FullName C:\Windows\System32\drivers\vfpext.sys -Force
After reboot, Test-Path C:\Windows\System32\drivers\vfpext.sys returned True and Cowork works. This suggests the servicing path isn't projecting the driver on some x64 configs, not just ARM64.
Confirming this exact issue on a current, fully-patched build — no reinstall needed to hit it, which may be a useful data point since it rules out "stale build" as a cause.
Environment
Verified state
Steps taken (all unsuccessful)
Enable-WindowsOptionalFeature, rebootedDISM /Online /Cleanup-Image /RestoreHealth— completed successfullysfc /scannow— no corruption foundvfpext.sys— still absentNotes
vmcomputeandhnsare both confirmed running, so this is isolated to thevfpextdriver specifically not being deployed — matches the pattern in this issue and #78866/#78858, but on a build that's already current (26200.8875), not one needing a reinstall or update to reach parity.