[BUG] CoworkVMService stops between sessions and cannot be restarted by the app

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 feature intermittently fails to start with the error:

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

Reinstalling the app resolves it temporarily, but the error returns after one or more sessions.

Root Cause
CoworkVMService is a Windows service that manages the Linux VM backing the cowork workspace. It starts successfully at Claude launch but stops itself between sessions to free resources. This is expected behavior. The problem is that when the user subsequently opens the cowork workspace, the Claude app — running in the MSIX sandbox — fails to restart the service reliably.

The service itself starts and runs correctly when started externally (e.g., via Start-Service CoworkVMService in PowerShell). The issue is the app's ability to trigger the restart.

MSIX ACL Lockout Compounds the Problem
The CoworkVMService security descriptor is locked to the MSIX package. Its DACL does not grant SERVICE_CHANGE_CONFIG rights to Administrators or SYSTEM:

D:(A;;CCLCSWRPWPDTLOCRRC;;;AU)
(A;;CCDCLCSWRPWPDTLOCRSDRCWDWO;;;S-1-5-80-[service SID])
This means:

sc.exe failure CoworkVMService ... fails with Access is denied, even from an elevated Administrator session
Service recovery options (auto-restart on failure) cannot be configured by the user or any external tool
The service also logs: Warning: failed to open service for recovery config: Access is denied on every startup, indicating it cannot configure its own recovery settings either
Workaround Required
A scheduled task running as SYSTEM must be manually created to poll the service every 2 minutes and restart it if stopped:

$action = New-ScheduledTaskAction -Execute "PowerShell.exe"
-Argument "-NonInteractive -WindowStyle Hidden -Command "if ((Get-Service CoworkVMService).Status -ne 'Running') { Start-Service CoworkVMService }""
$triggerBoot = New-ScheduledTaskTrigger -AtStartup
$triggerRepeat = New-ScheduledTaskTrigger -Once -At (Get-Date)
-RepetitionInterval (New-TimeSpan -Minutes 2)
-RepetitionDuration (New-TimeSpan -Days 3650)
$settings = New-ScheduledTaskSettingsSet -ExecutionTimeLimit (New-TimeSpan -Minutes 1) -StartWhenAvailable
$principal = New-ScheduledTaskPrincipal -UserId "SYSTEM" -LogonType ServiceAccount -RunLevel Highest
Register-ScheduledTask -TaskName "Claude CoworkVM Service Monitor"
-Action $action -Trigger $triggerBoot,$triggerRepeat `
-Settings $settings -Principal $principal -Force
This is not something a typical user should need to do.

What Should Happen?

Either:

The MSIX package should configure CoworkVMService recovery options at install time (before the ACL is locked), so the service auto-restarts on its own, or
The app should have sufficient inter-process permissions to start its own registered service reliably, or
The service should remain running while Claude is open rather than stopping between cowork sessions

Error Messages/Logs

Steps to Reproduce

Occurs after install and happens by just being in the Cowork area (tab).

Claude Model

Sonnet (default)

Is this a regression?

I don't know

Last Working Version

_No response_

Claude Code Version

v1.11187.4

Platform

Anthropic API

Operating System

Windows

Terminal/Shell

PowerShell

Additional Information

Both issues (also Issue #65885) stem from the MSIX packaging model creating permission and sandboxing constraints that the app does not adequately handle. Neither issue existed in the prior non-MSIX distribution. Both required advanced troubleshooting (reading Electron logs, inspecting service ACLs, creating scheduled tasks) that is far beyond what a typical user can reasonably be expected to perform. Users encountering these issues will simply conclude the app is broken.

System: Windows 11 Home 10.0.26200 | Claude v1.11187.4 (MSIX/Anthropic Download) | NVIDIA + Intel dual-GPU laptop