[BUG] Cowork — vmcompute (Hyper-V Host Compute Service) terminates with "General access denied error" (0x80070005); workspace never starts despite readiness check PASS/SUPPORTED

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 Cowork workspace fails to start with "VM service not running. The service failed to start." The Hyper-V Host Compute Service (vmcompute) terminates immediately on start with "General access denied error" (0x80070005). This happens even though the official Cowork readiness check returns SUPPORTED with every item PASS and all Windows prerequisites are correctly configured (hypervisor running, all VM optional features enabled, Memory Integrity off, correct user-rights for SID S-1-5-83-0). vmcompute sometimes starts for a few seconds (workspace shows "still starting") then falls back to Stopped, leaving the VM permanently stuck.

What Should Happen?

The Cowork workspace (Linux VM) should boot normally and become available, since the readiness check reports the system as SUPPORTED.

Error Messages/Logs

Event Viewer (System log, Service Control Manager):
"Service 'Hyper-V Host Compute Service' terminated with the following error: General access denied error." (code 0x80070005 / E_ACCESSDENIED), logged on every start attempt.

Start-Service vmcompute (as administrator) fails with: StartServiceFailed.

Service state: CoworkVMService = Running (Automatic); vmcompute = Stopped (Manual).

Readiness check result: SUPPORTED (all PASS; one [WARN] "VM service logon right — could not query LSA deny: {Access Denied}", which is only the checker lacking privilege to read the LSA deny right — verified via secedit that SeServiceLogonRight contains S-1-5-83-0 and no SeDenyServiceLogonRight entry exists).

Steps to Reproduce

1. Windows 11 Home with Kaspersky Premium active.
2. Enable VirtualMachinePlatform, HypervisorPlatform, WSL; set bcdedit hypervisorlaunchtype auto; reboot (HypervisorPresent = True).
3. Open Claude Desktop and try to start the Cowork workspace.
4. Observe "VM service not running. The service failed to start." and the vmcompute "General access denied error" in Event Viewer.

Restarting Claude/PC, reinstall guidance, and adding vmcompute to Kaspersky Trusted do not resolve it.

Claude Model

Opus

Is this a regression?

No, this never worked

Last Working Version

_No response_

Claude Code Version

Claude Desktop (Cowork)

Platform

Anthropic API

Operating System

Windows

Terminal/Shell

PowerShell

Additional Information

_No response_