[BUG] Claude Cowork fails on Windows 11 25H2 - CoworkVMService fails to start

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?

Claude Cowork workspace fails to start with error:
"VM service not running. The service failed to start."
CoworkVMService fails to start on Windows 11 25H2.

What Should Happen?

Claude Cowork should start the VM and workspace successfully.

Error Messages/Logs

CoworkVMService: Failed to start service 'Claude (CoworkVMService)'
luafv driver blocked: ERROR_DRIVER_BLOCKED (1275)
Log: "VM service not running. The service failed to start."

Steps to Reproduce

1. Install Claude on Windows 11 25H2 (Build 26200.7840)
2. Try to open Claude Cowork workspace
3. Error appears: "VM service not running. The service failed to start."

Claude Model

None

Is this a regression?

Yes, this worked in a previous version

Last Working Version

_No response_

Claude Code Version

1.1.5368.0

Platform

Anthropic API

Operating System

Windows

Terminal/Shell

Other

Additional Information

• Hyper-V enabled
• Virtual Machine Platform enabled
• vmms and vmcompute services running
• Memory Integrity disabled
• luafv driver blocked from loading on this Windows build
• CoworkVMService starts but immediately exits (under 1 second)
• Device: HP ENVY 15