Cowork VM service fails to start on Windows 11 Pro after Claude Desktop update

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?

Related issues exist (#27801, #29428, #25206) but none match this exact regression tied to today's Claude Desktop auto-update.

Cowork was fully functional yesterday. After a Claude Desktop update pushed this morning, Cowork fails to start.

Initial error on launch:
Claude Code process exited with code 1

After a full PC reboot, the error changed to:
Failed to start Claude's workspace. VM service not running. The service failed to start.

Cowork is completely unusable. No tasks can be run.

What Should Happen?

Cowork workspace VM should start successfully and remain running after Claude Desktop auto-updates. The VM service should not break across Desktop version bumps.

Error Messages/Logs

Error 1 (initial):
Claude Code process exited with code 1

Error 2 (after reboot):
Failed to start Claude's workspace
VM service not running. The service failed to start.
Restarting Claude or your computer sometimes resolves this. If it persists, you can reinstall the workspace.

PowerShell output during troubleshooting:
PS> New-NetNat -Name "cowork-vm-nat" -InternalIPInterfaceAddressPrefix "172.16.0.0/24"
New-NetNat: Invalid class

PS> Import-Module NetNat -Force
PS> Get-NetNat
Get-NetNat: Invalid class

PS> winmgmt /verifyrepository
WMI repository is consistent

PS> sfc /scannow
Windows Resource Protection did not find any integrity violations.

Steps to Reproduce

1. Have Cowork working normally on Windows 11 Pro
2. Receive Claude Desktop auto-update
3. Launch Claude Desktop
4. Open Cowork
5. Observe "Claude Code process exited with code 1" error
6. Reboot PC
7. Reopen Cowork
8. Observe "VM service not running" error

Claude Model

None

Is this a regression?

Yes, this worked in a previous version

Last Working Version

Unknown - worked 4/15/2026 prior to auto-update

Claude Code Version

2.1.110 (Claude Code)

Platform

Anthropic API

Operating System

Windows

Terminal/Shell

PowerShell

Additional Information

Troubleshooting performed prior to filing:

• Killed cowork-svc process and relaunched Claude Desktop — no change
• Full PC reboot — no change
• Reinstalled Claude Desktop — no change
• Attempted New-NetNat workaround from issue #27010 — returns "Invalid class"
• Import-Module NetNat followed by Get-NetNat — returns "Invalid class"
• Confirmed HNS, SharedAccess, vmcompute, mpssvc services are all running
• winmgmt /verifyrepository — WMI repository consistent
• sfc /scannow — no integrity violations
• Attempted manual NetNat MOF re-registration from WinSxS — syntax errors

Environment details:

• Windows 11 Pro 25H2, Build 26200.8037
• Last Windows Update: 3/15/2026 (ruled out as trigger)
• Hyper-V: Enabled

Related issues with matching symptom pattern: #27801, #29428, #25206

Note: During troubleshooting, the .claude folder in user profile was renamed to .claude.bak and later renamed back. Reverted before final state, flagging for transparency.

Screenshots attached.

<img width="454" height="238" alt="Image" src="https://github.com/user-attachments/assets/90995c4f-6f59-4db7-a626-86f1e854ba8a" />