Windows MSIX: Claude fails to launch after update (AppX container error 0x80070020)

Environment

• Product: Claude for Windows (desktop app)
• Package: Claude_1.2278.0.0_x64__pzs8sxrjxfjjc
• Install type: MSIX/AppX (C:\Program Files\WindowsApps)
• OS: Windows
• Reproducibility: Repeats after updates

Summary

After installing a Claude update on Windows, the app cannot be relaunched. Windows reports a "file is being used by another program" error. Claude fails to start until reinstall or reboot.

Steps to Reproduce

1. Claude is running
2. Update installs
3. Try to relaunch Claude
4. Launch fails repeatedly

Observed Behavior

• AppX/AppModel launch failures with error 2147942432 (0x80070020 / sharing violation)
• Event ID 208 (Microsoft-Windows-AppModel-Runtime/Admin): Claude.exe launch fails
• Event ID 215: Desktop AppX container creation fails for the package
• Packaged service CoworkVMService stops/starts around the same timestamps but doesn't resolve the issue

Event Viewer Evidence

AppModel-Runtime (Event 208):

Launch of Claude.exe fails with ErrorCode 2147942432 (0x80070020)
Times: 17:55:51, 17:56:10, 17:56:13, 17:57:56-17:57:59, 18:01:46-18:01:49, 18:20:11-18:20:15

AppModel-Runtime (Event 215):

Desktop AppX container creation fails for Claude_1.2278.0.0_x64__pzs8sxrjxfjjc
Error: 2147942432 (0x80070020)

CoworkVMService (Application log):

2026-04-14 17:55:47 service stopped
2026-04-14 17:55:51 service started
2026-04-14 18:01:47 service stopped
2026-04-14 18:01:48 service started

Key Finding

The package registers a packaged Windows service:

• Service: CoworkVMService (Display name: "Claude")
• Type: WIN32_PACKAGED_PROCESS
• Startup: AUTO_START
• Account: LocalSystem
• Binary: cowork-svc.exe
• Declared in AppxManifest.xml as windows.service

Hypothesis

Bug in the MSIX/AppX update path involving the packaged service CoworkVMService and the transition between old/new package container state. The service holds a lock that prevents AppX container creation for the new package version.

Workarounds Attempted

• Stopping CoworkVMService manually: Does not resolve — relaunching Claude restarts the service and the error recurs
• Reboot / reinstall: Works, but should not be necessary after a normal update

Relevant Logs

• C:\ProgramData\Claude\Logs\cowork-service.log
• Event Viewer: Microsoft-Windows-AppModel-Runtime/Admin
• Event Viewer: Microsoft-Windows-AppXDeployment-Server/Operational
• Event Viewer: Application (provider: CoworkVMService)

Expected Behavior

Claude should update and relaunch normally without leaving the package in a broken state.