Windows: CoworkVMService stops and fails to auto-restart, causing persistent 'Failed to start Claude'\''s workspace' error

Bug Description

On Windows, the Claude Desktop workspace (cowork) feature frequently breaks with the error:

Failed to start Claude's workspace VM service not running. The service failed to start.

The root cause is that the Windows service CoworkVMService (cowork-svc.exe) stops and is not automatically restarted by the Claude Desktop app. Once stopped, every attempt to use the workspace fails with the above error repeating every ~60 seconds in main.log.

Root Cause Analysis

1. CoworkVMService is a Windows service (StartType=Automatic) that manages the HCS-based VM for Claude's workspace
2. The service has an idle timeout mechanism — when all Claude Desktop subscribers disconnect and no sessions are active, the service eventually stops itself
3. The service has no failure recovery actions configured (no restart-on-failure policy), and because it's an MSIX-packaged service, recovery settings cannot be modified via sc.exe failure
4. When Claude Desktop subsequently tries to start the workspace, it reports "VM service not running. The service failed to start." but does not successfully restart the service
5. The only fix is manually running Start-Service CoworkVMService in an elevated PowerShell, or rebooting

Timeline from logs

17:27:59 - CoworkVMService: "[VM] VM stopped", "[Server] Session has no active connections, idle timeout starts"
17:28~17:57 - Service running idle, logging "No subscribers, checking 1 sessions for idle timeout..."
17:58:05 - Claude Desktop reconnects, VM starts successfully via HCS
18:03:06 - Claude Desktop quits, VM shuts down cleanly
18:11:06 - Last CoworkVMService log entry: "[IdleCheck] 1 active subscribers, skipping idle check"
(service stops silently between 18:11 and 18:20)
18:20:57 - Claude Desktop restarts (after user-triggered reinstall)
18:21:00 - VM module loaded, but CoworkVMService is already Stopped
18:21:05 - Error: "VM service not running. The service failed to start."
(error repeats every 60 seconds indefinitely)

Environment

• OS: Windows 11 Pro 10.0.26200
• Claude Desktop version: 1.1.7714.0 (Microsoft Store / MSIX)
• Service path: C:\Program Files\WindowsApps\Claude_1.1.7714.0_x64__pzs8sxrjxfjjc\app\resources\cowork-svc.exe
• Windows features: VirtualMachinePlatform ✅, WSL ✅, Microsoft-Hyper-V ❌ (not required — uses HCS directly)
• vmcompute service: Running

Suggested Fix

1. Claude Desktop should more robustly handle starting CoworkVMService when it's found in a Stopped state — the current "The service failed to start" path seems to give up too easily
2. The MSIX package manifest should configure service failure recovery actions (restart on failure) for CoworkVMService
3. Consider adding a retry mechanism with delay when the service start fails
4. The service's idle self-shutdown behavior should be reconsidered — stopping a Windows service that the app depends on creates a fragile startup dependency

Workaround

Run in elevated PowerShell:

Start-Service CoworkVMService

Then restart Claude Desktop or retry the workspace.