[BUG] Claude Desktop update fails with 0x80073CF6 when CoworkVMService is running (Windows) #49655

Preflight Checklist

• I have searched existing issues and this hasn't been reported yet
• This is a single bug report (please file separate reports for different bugs)
• I am using the latest version of Claude Code

What's Wrong?

**Claude Desktop fails to update/reinstall on Windows with HRESULT 0x80073CF6 (ERROR_PACKAGES_IN_USE) when CoworkVMService is running, even after Claude
Desktop is fully closed.

The AppX installer cannot delete the Helium virtual registry hive files because CoworkVMService holds kernel-level locks on them:

• C:\Users<user>\AppData\Local\Packages\Claude_pzs8sxrjxfjjc\SystemAppData\Helium\User.dat
• C:\Users<user>\AppData\Local\Packages\Claude_pzs8sxrjxfjjc\SystemAppData\Helium\UserClasses.dat

These locks cannot be released without a full system reboot, making it impossible to update Claude while any server/service is running.**

What Should Happen?

The Claude installer should automatically stop CoworkVMService and related processes (cowork-svc, parsecd, chrome-native-host) before attempting the MSIX
package update, then restart them after installation completes.

Error Messages/Logs

MSIX installation failed: AddPackage failed: AddPackage failed with HRESULT 0x80073CF6

  AppX deployment log:
  - Error deleting Helium\User.dat: 0x20 (ERROR_SHARING_VIOLATION)
  - Error deleting Helium\UserClasses.dat: 0x20 (ERROR_SHARING_VIOLATION)
  - Error 0xD0074005: Cannot notify BrokerInfrastructure service about package state change

Steps to Reproduce

1. Install Claude Desktop (MSIX) with Cowork feature enabled
2. Launch Claude Desktop — CoworkVMService starts automatically
3. Close Claude Desktop completely
4. Download and run the new Claude Setup.exe installer
5. Installation fails with: AddPackage failed with HRESULT 0x80073CF6

Workaround (requires manual step before every update):
Stop-Service CoworkVMService -Force
Stop-Process -Name cowork-svc, parsecd, chrome-native-host -Force -ErrorAction SilentlyContinue

Claude Code Version
Claude Desktop 1.3036.0.0

Operating System
Windows 11 Pro 10.0.26100

Terminal/Shell
PowerShell (Administrator)

Claude Model

Other

Is this a regression?

Yes, this worked in a previous version

Last Working Version

No response

Claude Code Version

Claude Desktop 1.3036.0.0

Platform

Anthropic API

Operating System

Windows

Terminal/Shell

Terminal.app (macOS)

Additional Information

• This is a recurring issue: every Claude Desktop update requires a full system reboot if CoworkVMService has been running
• The Helium hive files are locked at kernel level — handle64.exe (Sysinternals) cannot detect the lock
• reg unload fails with "Access is denied" even from Administrator
• Only a full system restart releases the kernel-level hive locks
• Users running servers or long-running processes cannot reboot just to update Claude