[BUG] Cowork: VM service not running — DCOM 10016 / exit code 1066 on Win11 Home→Pro upgrade (Build 26200)

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?

CoworkVMService fails to start with exit code 1066 ("Incorrect function")
due to a DCOM Local Activation permission error. This occurred after an
in-place upgrade from Windows 11 Home to Pro.

This matches the root cause described in #30179 and #36801 but is still
unresolved on the latest build.

What Should Happen?

CoworkVMService should start successfully after an in-place Windows 11
Home→Pro upgrade with Hyper-V fully enabled. The MSIX app container
should have correct DCOM permissions to activate the Hyper-V COM
interface, and the VM should boot and provide a functional workspace.

Specifically:

• CoworkVMService should start without exit code 1066
• APPID {15C20B67-12E7-4BB6-92BB-7AFF07997402} should either be

registered with correct permissions post-upgrade, or the installer
should repair DCOM permissions on reinstall

• hcsdiag list should show the cowork-vm after startup
• The in-place Home→Pro upgrade path should be a supported and tested

configuration given that users are being advised to upgrade to Pro
to resolve Cowork issues on Home

Error Messages/Logs

System Event Log — Event 10016 (DCOM):
The application-specific permission settings do not grant Local Activation 
permission for the COM Server application with CLSID 
{2593F8B9-4EAF-457C-B68A-50F6B8EA6B54} and APPID 
{15C20B67-12E7-4BB6-92BB-7AFF07997402} to the user AustinsPC\goodn 
running in application container Claude_1.1.8629.0_x64__pzs8sxrjxfjjc.

Service status:
- CoworkVMService: Stopped
- ExitCode: 1066

cowork_vm_node.log — fails at this step every time:
[info] [VM:start] Configuring Windows VM service...
[error] [VM:start] Startup failed: VM service not running. 
The service failed to start.

Hyper-V Compute log — never progresses past:
"The Host Compute Service is starting."
No VM creation events ever appear.

Steps to Reproduce

1. Start with Windows 11 Home
2. Upgrade to Windows 11 Pro in-place via product key
3. Enable Hyper-V: Enable-WindowsOptionalFeature -Online

-FeatureName Microsoft-Hyper-V -All

1. Reboot, confirm vmcompute is running
2. Fresh install Claude Desktop latest version
3. Open Cowork → "VM service not running. The service failed to start."

Claude Model

Sonnet (default)

Is this a regression?

No, this never worked

Last Working Version

_No response_

Claude Code Version

v1.1.8629 (64248d)

Platform

Anthropic API

Operating System

Windows

Terminal/Shell

PowerShell

Additional Information

Environment

• OS: Windows 11 Pro (in-place upgrade from Home), Build 26200
• Claude Desktop: v1.1.8629 (64248d)
• CPU: AMD (ASUS ROG system)
• Hyper-V: Enabled (Microsoft-Hyper-V-All via PowerShell)
• vmcompute: Running
• WSL2: 2.6.3 installed
• VirtualMachinePlatform: Enabled
• HypervisorPlatform: Enabled
• systeminfo: "A hypervisor has been detected"

Additional Diagnostics

• APPID {15C20B67-12E7-4BB6-92BB-7AFF07997402} not present in registry

(Get-ChildItem returns empty) — cannot fix via Component Services

• hcsdiag list returns empty despite vmcompute running
• Start-Service CoworkVMService fails immediately with StartServiceFailed
• Full uninstall/reinstall, VM bundle deletion, and reboot do not resolve

Related Issues

#30179 #36801 #27801 #27010