[BUG] Cowork: "VM service not running" — DCOM 10016 blocks CoworkVMService start from MSIX container (Win11 Home→Pro upgrade)

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. The Claude MSIX app container cannot activate the Hyper-V COM object needed to boot the VM. This persists through full uninstall/reinstall, VM bundle deletion, manual sessiondata.vhdx creation, and manual NetNat creation.

Timeline:

1. Originally on Windows 11 Home — Cowork failed with "VM service not running"
2. Attempted batch script Hyper-V install (partial, cancelled mid-run)
3. Purchased and applied Windows 11 Pro license (in-place upgrade)
4. Enabled Hyper-V via Enable-WindowsOptionalFeature -Online -FeatureName Microsoft-Hyper-V -All
5. Confirmed Hyper-V state: Enabled, vmms service: Running
6. Fully uninstalled Claude Desktop, deleted all app data (%APPDATA%\Claude, %LOCALAPPDATA%\Claude,
7. %LOCALAPPDATA%\Packages\Claude_pzs8sxrjxfjjc)
8. Rebooted, fresh install of Claude Desktop v1.1.4498.0
9. Cowork UI loads, folder selection works, but VM never starts

Additional issues found during debugging:

• sessiondata.vhdx not auto-created by Cowork — had to manually create via New-VHD
• NetNat not auto-created — had to manually run New-NetNat -Name "cowork-vm-nat" -InternalIPInterfaceAddressPrefix "172.16.0.0/24"
• DCOM APPID {15C20B67-12E7-4BB6-92BB-7AFF07997402} not visible in Component Services (dcomcnfg) — cannot manually fix permissions

Related issues: #25663, #27801, #25206, #27010, #24918

What Should Happen?

CoworkVMService should start successfully, create the VM, and provide a functional workspace. The service should auto-create sessiondata.vhdx and the NetNat rule, and the MSIX container should have proper DCOM permissions to activate the Hyper-V COM interface.****

Error Messages/Logs

-System Event Log — Event 7024:

The Claude service terminated with the following service-specific error:
Incorrect function.

-System Event Log — Event 10016 (DCOM permission error):

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 <MACHINE>\<USER> SID (<REDACTED>) 
from address LocalHost (Using LRPC) running in the application container 
Claude_1.1.4498.0_x64__pzs8sxrjxfjjc SID (Unavailable). 
This security permission can be modified using the Component Services administrative tool.

-Service status:

PS> Get-CimInstance Win32_Service -Filter "Name='CoworkVMService'" | Select PathName, State, ExitCode
PathName: "C:\Program Files\WindowsApps\Claude_1.1.4498.0_x64__pzs8sxrjxfjjc\app\resources\cowork-svc.exe"
State: Stopped
ExitCode: 1066

-Hyper-V Compute events (no VM creation since Feb 9):

3/2/2026 2:20:57 PM  The Host Compute Service is starting.
3/2/2026 2:11:07 PM  The Host Compute Service is starting.
3/2/2026 1:59:08 PM  The Host Compute Service is starting.
3/2/2026 1:58:10 PM  The Host Compute Service is starting.

-cowork_vm_node.log (tail):

2026-03-02 14:34:09 [info] All files ready in C:\Users\<USER>\AppData\Roaming\Claude\vm_bundles\claudevm.bundle

-VM bundle contents (all downloaded, checksums validated):

rootfs.vhdx      9,252,634,624 bytes
rootfs.vhdx.zst  2,326,875,206 bytes
vmlinuz             14,965,128 bytes
initrd             175,549,736 bytes
sessiondata.vhdx     4,194,304 bytes  (manually created)
smol-bin.x64.vhdx   37,748,736 bytes  (present in app resources)
Network: Default Switch on 172.22.16.0/20 (no conflict). Manually created cowork-vm-nat on 172.16.0.0/24 — service still fails.

Steps to Reproduce

1. Start with Windows 11 Home (Build 26200.7922)
2. Upgrade to Windows 11 Pro in-place via product key
3. Enable Hyper-V: Enable-WindowsOptionalFeature -Online -FeatureName Microsoft-Hyper-V -All
4. Reboot, confirm vmms service is running
5. Fresh install Claude Desktop v1.1.4498.0
6. Open Cowork → select folder → "VM service not running. The service failed to start."

Claude Model

None

Is this a regression?

No, this never worked

Last Working Version

_No response_

Claude Code Version

Claude Desktop v1.1.4498.0

Platform

Other

Operating System

Windows

Terminal/Shell

PowerShell

Additional Information

• Hyper-V is confirmed enabled and vmms is running — the issue is specifically DCOM permissions for the MSIX container
• The APPID {15C20B67-12E7-4BB6-92BB-7AFF07997402} is not visible in Component Services, so the user cannot manually fix the permission
• A disable/re-enable of Hyper-V (Disable-WindowsOptionalFeature then Enable-WindowsOptionalFeature) did not resolve the DCOM registration
• The in-place Home→Pro upgrade path may leave DCOM/COM registrations in a state that the Claude MSIX installer doesn't account for