[BUG] Cowork impossible on MSI MPG X570 / Ryzen 9 3900X — vmms service missing, Hyper-V causes boot failure

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?

Cowork is impossible to use on this system. Root cause identified: the vmms service (Virtual Machine Management Service) does not exist. Running Get-Service vmms returns "No service found". Without vmms, the Cowork VM cannot start. Enabling Hyper-V or Virtual Machine Platform causes complete Windows 11 boot failure every time — System Restore is required to recover.

What Should Happen?

Cowork should either install the vmms service correctly during setup, or support an alternative virtualization backend (such as WSL2) for systems where Hyper-V causes boot failure.

Error Messages/Logs

Get-Service vmms → "No service found"
Cowork Readiness Check → "Virtual Machine Platform — missing services: vmcompute, HNS, vfpext"
Enabling Virtual Machine Platform → Windows 11 boot failure, automatic repair loop
System Restore required to recover after every attempt
Related issues: #35728, #32409

Steps to Reproduce

1. Install Claude Desktop on Windows 11 Pro (MSI MPG X570 / AMD Ryzen 9 3900X)
2. Run Get-Service vmms in PowerShell — returns "No service found"
3. Enable Virtual Machine Platform and restart
4. Windows fails to boot — automatic repair loop
5. System Restore required to recover

Claude Model

None

Is this a regression?

No, this never worked

Last Working Version

_No response_

Claude Code Version

Claude 1.1.7053 (cc1949) 2026-03-16

Platform

Other

Operating System

Windows

Terminal/Shell

PowerShell

Additional Information

CPU: AMD Ryzen 9 3900X — MSI MPG X570 Gaming Edge WiFi — 64GB RAM — RTX 4080 SUPER — Windows 11 Pro Build 26200. UEFI mode, Secure Boot enabled, SVM enabled, CSM disabled. Claude Desktop chat works perfectly. Issue is specific to Cowork virtualization layer.