How to Fix Cowork VM Service on Windows 11

A detailed diagnosis reveals why Cowork's VM service fails to start on Windows 11 systems, particularly after a Home to Pro upgrade. The root cause is a missing DCOM registry entry that blocks communication with Hyper-V.

The Problem

Users encounter the error: "Failed to start Claude's workspace — VM service not running. The service failed to start." The CoworkVMService exits with code 1066 ("Incorrect function") due to a DCOM permission error (Event ID 10016). The Claude MSIX container cannot activate the required Hyper-V COM interface.

Root Cause

The specific APPID {15C20B67-12E7-4BB6-92BB-7AFF07997402}, which needs Local Activation permission for DCOM, is completely absent from the Windows registry. This prevents the standard DCOM fix (taking ownership in the registry and granting permissions in Component Services) because there's nothing to modify.

User Setup and Attempted Fixes

The diagnosis was performed on:

Windows 11 Pro (upgraded from Home)
ASUS ROG system
Claude Desktop v1.1.8629
Hyper-V fully enabled, vmcompute running, WSL2 installed

Attempted solutions that did not work:

Upgrading from Windows 11 Home to Pro
Enabling Hyper-V, VirtualMachinePlatform, and HypervisorPlatform
Installing WSL2
Deleting and re-downloading the VM bundle
Manually running Start-Service CoworkVMService
Checking Component Services via dcomcnfg

Why Only Anthropic Can Fix This

The missing APPID is part of Anthropic's own COM registration. Their installer needs to create this registry entry with the correct permissions. Users cannot safely create this DCOM configuration themselves.