[BUG] Cowork says "Virtualization is not available" — but Hyper-V is alive and well. Claude just won't believe it.

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?

The Irony

I asked Claude itself to help me fix this error. After deep research, Claude's own conclusion was: "This is a known bug in Claude Desktop. There's nothing you can do on your end." So here I am, filing the bug that Claude told me to file about Claude. We've come full circle. 🎯

What Happens

Claude Desktop shows: "Virtualization is not available — Claude's workspace requires Hyper-V, but the virtualization service isn't responding. Restart your computer to resolve this."

Spoiler: restarting does not resolve this.

What I've Tried (Everything)

1. ✅ Verified systeminfo — all four Hyper-V requirements show Yes
2. ✅ Task Manager → CPU → Virtualization: Enabled
3. ✅ Ran bcdedit /set hypervisorlaunchtype auto — "completed successfully"
4. ✅ Restarted. Multiple times. Lost count.
5. ✅ Hyper-V services (vmms, vmcompute) running and set to Automatic
6. ✅ BIOS virtualization (VT-x) confirmed enabled
7. ✅ No VPN running
8. ✅ Prayed to the Hyper-V gods. No response.

None of the above made any difference. The error persists stubbornly.

Environment

• OS: Windows 11 Pro x64
• Claude Desktop: Latest version (as of Feb 28, 2026)
• Hyper-V: Fully enabled, functional, and confirmed by every diagnostic tool available
• Other VM software: Hyper-V works fine for everything else — just not for Claude

Expected Behavior

Cowork should detect that Hyper-V is enabled and launch its workspace VM.

Actual Behavior

Claude Desktop refuses to acknowledge that virtualization exists on a system where it demonstrably does. It's like telling someone with perfect 20/20 vision that they can't see.

Related Issues

This appears to be the same detection bug reported in #27384, #27316, #27350, and #27330. The common thread: Hyper-V works, Claude doesn't believe it.

Impact

Cowork is completely unusable. The only workaround is using claude.ai in the browser, which kind of defeats the purpose of having a desktop app with workspace capabilities.

Please prioritize this fix. Many users are affected and there's no user-side workaround.

What Should Happen?

Cowork should detect that Hyper-V is enabled and running, and successfully launch its workspace VM. Instead, it shows "Virtualization is not available" despite all system checks confirming virtualization is fully operational.

Error Messages/Logs

Error message in Claude Desktop:
"Virtualization is not available — Claude's workspace requires Hyper-V, but the virtualization service isn't responding. Restart your computer to resolve this."

System verification:
> bcdedit /set hypervisorlaunchtype auto
The operation completed successfully.

> systeminfo | findstr /i "hyper"
All four Hyper-V requirements: Yes
Task Manager → CPU → Virtualization: Enabled

Steps to Reproduce

1. Install Claude Desktop on Windows 11 Pro x64
2. Ensure Hyper-V is fully enabled (verified via systeminfo — all four requirements show "Yes")
3. Ensure virtualization is enabled in BIOS (VT-x)
4. Run bcdedit /set hypervisorlaunchtype auto and restart
5. Open Claude Desktop
6. Try to use Cowork workspace
7. Error appears: "Virtualization is not available — Claude's workspace requires Hyper-V, but the virtualization service isn't responding. Restart your computer to resolve this."
8. Restart computer — error persists
9. Repeat steps 5-8 indefinitely with no change

Claude Model

None

Is this a regression?

Yes, this worked in a previous version

Last Working Version

N/A - Cowork never worked on this machine

Claude Code Version

Latest (Feb 28, 2026)

Platform

Anthropic API

Operating System

Windows

Terminal/Shell

Windows Terminal

Additional Information

_No response_