[BUG] Cowork "Virtualization is not enabled" error despite hypervisor active — regression on Windows 11 Home 25H2

[zyzone03]

Preflight Checklist

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

What's Wrong?

Cowork displays "Virtualization is not enabled. Claude's workspace requires hardware virtualization (Hyper-V)" error, despite all virtualization features being confirmed active and working correctly at the system level.

This is a regression — Cowork was working fine on this exact same Windows 11 Home configuration until a few days ago. The issue started appearing after a recent Claude Desktop update.

System verification confirms virtualization is fully operational:

Check | Result -- | -- Task Manager → Virtualization | ✅ Enabled vmcompute service | ✅ Running vmms service | ✅ Running (Automatic) systeminfo | "A hypervisor has been detected. Features required for Hyper-V will not be displayed." VirtualMachinePlatform | ✅ Enabled HypervisorPlatform | ✅ Enabled Microsoft-Windows-Subsystem-Linux | ✅ Enabled WSL2 + Ubuntu | ✅ Installed and working

Troubleshooting already attempted (all failed):

1. Disabled and re-enabled all virtualization features (VirtualMachinePlatform, HypervisorPlatform, WSL) via DISM
2. Reinstalled WSL2 with Ubuntu distribution
3. Uninstalled and reinstalled Claude Desktop
4. Full OS reset (Remove Everything) — performed a complete Windows reset, reinstalled everything from scratch
5. Multiple reboots throughout the process

None of these resolved the issue. The error persists even after a full OS reset, which strongly suggests this is a Claude Desktop app-side detection bug, not a system configuration issue.

What Should Happen?

Cowork should detect the active hypervisor and start the workspace successfully, as it did before the recent update.

Error Messages/Logs

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

Note: Could not locate cowork_vm_node.log at %APPDATA%\Claude\logs\ — the Claude folder does not exist at that path. Log directory location for MSIX installs may differ.

Steps to Reproduce

Install Claude Desktop (latest version) on Windows 11 Home 25H2
Ensure all virtualization features are enabled and verified working
Open Claude Desktop
Switch to Cowork tab
Observe: "Virtualization is not enabled" error appears immediately

Claude Model

Sonnet (default)

Is this a regression?

Yes, this worked in a previous version

Last Working Version

No response

Claude Code Version

Claude Desktop (latest MSIX install from claude.ai/download). This is Cowork on Claude Desktop, not Claude Code CLI.

Platform

Anthropic API

Operating System

Windows

Terminal/Shell

PowerShell

Additional Information

This is NOT a system virtualization issue — all system-level checks confirm virtualization is active and functional.
This is a regression — the same hardware + OS combination was running Cowork successfully before the recent update.
A full OS reset was performed (Remove Everything), ruling out any corrupted system state.
Regular Chat mode works perfectly in the same Claude Desktop app — only Cowork is affected.
The app appears to have a faulty virtualization detection mechanism that fails on Windows 11 Home despite the hypervisor being active.
Possibly related (but different symptoms): #24918, #25241, #25663

[github-actions]

Found 3 possible duplicate issues:

1. Cowork VM: 'Virtualization is not enabled' after update to 1.1.3918 - yukonSilver unsupported regression #27354
2. [BUG] Cowork regression on Windows — yukonSilver marked unsupported after update to v1.1.3918 (was working on previous version) #27323
3. [BUG] VM reports hardware_virt+gisabled after auto=update to v1.1.3918 --- was working fine on v1.1.3830 #27340

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

[Carobelli]

Same issue here. Dell Precision 7770, Windows Pro (domain-joined), Intel 12th Gen, x64.

From cowork_vm_node.log:

• [cleanupVMBundleIfUnsupported] yukonSilver not supported (status=unsupported)
• [startVM] VM not supported (win32/x64), skipping

Hyper-V: Enabled, VT-x/VT-d: Enabled in BIOS, CoworkVMService: Running.
Claude Desktop v1.1.3918 (a4b368).

Also a regression — Cowork was working previously on this same system.
Identical to #25136.

[albadrov-del]

Same issue on:
Windows 10 Education, Hyper-V enabled, virtualization enabled in BIOS, still showing "Virtualization is not enabled" error.

[elf1024-vot]

Same issue on Windows 11 Pro, had been working perfectly last night.

[antx0o0]

Same problem on Windows 11 Pro. Everything enabled. Hyper-V is enabled.

[Alex-Saad]

I have this issue can you investigate if it is indeed a bug or there is anything I can do?

Environment:

OS: Windows 11 Pro 25H2 (Build 26200.7462) — received via standard Windows Update, not Insider Programme
Hardware: Dell Latitude 7400 (physical machine, confirmed not a VM)
Installer: Claude Setup.exe (direct download from claude.ai/download)
Windows Features enabled:
Microsoft-Hyper-V-All ✅
HypervisorPlatform ✅
VirtualMachinePlatform ✅
WSL2 installed with Ubuntu ✅
Services running:
vmms (Running, Automatic)
vmcompute (Running, Manual)
hns (Running, Manual)
Relevant log output from cowork_vm_node.log:
2026-02-21 10:21:44 [info] [cleanupVMBundleIfUnsupported] yukonSilver not supported (status=unsupported), checking for stale bundle... 2026-02-21 10:22:37 [warn] [startVM] VM not supported (win32/x64), skipping
Error shown in UI:
"Virtualization is not enabled. Claude's workspace requires hardware virtualization (Hyper-V). Enable virtualization in your computer's BIOS/UEFI settings, then restart."
This error is misleading — hardware virtualization is confirmed enabled and all required features are active. The issue appears to be yukonSilver incorrectly flagging this win32/x64 environment as unsupported despite full Hyper-V support being present.

[dcox79]

Same issue here

[peiyuan-ran-huang]

Confirm same regression on Windows with Claude Desktop 1.1.3918.0: Cowork UI says "Virtualization is not enabled", but Hyper-V/WSL are enabled and working. Logs show Cowork incorrectly gates the VM as unsupported and skips startup.

Env

• Claude Desktop: 1.1.3918.0 (MSIX from claude.ai/download; not from Microsoft Store)
• Windows: 11 Enterprise 24H2 (OS Build 26100.7840)
• Hyper-V / VMP / WHP / WSL: Enabled (DISM), hypervisorlaunchtype=Auto
• Services running: vmms, vmcompute, WslService, CoworkVMService (Automatic)
• Hyper-V switches exist: Default Switch + cowork-vm-vnet (Get-VMSwitch)

Key log lines (cowork_vm_node.log)

• cleanupVMBundleIfUnsupported: yukonSilver not supported (status=unsupported)
• startVM: VM not supported (win32/x64), skipping
  (repeats continuously even after reboot)

Bundle reset attempt

• Renamed/moved: %APPDATA%\Claude\vm_bundles\claudevm.bundle -> claudevm.bundle.bak_20260221
• Rebooted + relaunched Claude: no new claudevm.bundle is recreated; the same unsupported/skipping loop persists.

Rollback not possible

• Get-AppxPackage Claude* shows only 1.1.3918.0
• C:\Program Files\WindowsApps contains only Claude_1.1.3918.0_x64__...

Also seeing multiple similar reports (e.g., #27354 ).

[MarshallOfSound]

Closing as duplicate of #27316 which was very rapidly fixed in the v1.1.3963 release

[Kii-910]

Environment

• Claude Desktop: 1.1.3918 (upgrading to 1.1.3963 if available)
• Platform: Windows 11 Home
• Subscription: Max

Background / Prior Issue
Previously affected by the API unreachability bug tracked in #24918. That issue was closed, but a new error has since appeared. The hardware and OS configuration have not changed between the two issues.

Current Error
Cowork tab now displays: "Virtualization is not enabled. Claude's workspace requires hardware virtualization (Hyper-V). Enable virtualization in your computer's BIOS/UEFI settings, then restart."

This error appears to be a false positive — virtualization has not been disabled and no system changes were made between the prior working state and this error appearing.

What's confirmed working on this machine

• Task Manager → CPU → Virtualization: Enabled
• Regular Claude Chat: working normally

Pattern worth flagging
This is the second distinct Cowork failure on the same machine and OS in under two weeks — first the API unreachability bug, now faulty virtualization detection. Both issues appeared after app updates without any change to the underlying hardware or OS configuration. This may suggest the app's preflight detection logic is fragile on Windows 11 Home specifically.

Request
Please confirm whether 1.1.3963 addresses this detection issue for Windows 11 Home users, or whether a separate fix is needed.