[BUG] Claude Desktop installation fails with HRESULT 0x80073CF6 — CoworkVMService blocks install even when stopped, WindowsApps folders undeletable

[pkuchta1990]

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 installation consistently fails at the MSIX registration step with AddPackage failed with HRESULT 0x80073CF6. The installer reports CoworkVMService already exists (potential conflict) and then fails to remove it with Access Denied — even when running with full elevation (Elevation type: Full, Is elevated: true).

ClaudeSetup.log

What Should Happen?

Steps to reproduce

1. Download Claude Setup.exe from claude.ai
2. Run installer (with or without administrator privileges)
3. Installer downloads and verifies MSIX successfully
4. Installation fails at AddPackage step

What I tried

• Restarted the computer multiple times
• Stopped CoworkVMService via Task Manager and PowerShell (sc.exe stop)
• Removed Claude AppX packages via Get-AppxPackage *Claude* | Remove-AppxPackage -AllUsers
• Deleted registry key HKCU:\Software\Classes\Local Settings\Software\Microsoft\Windows\CurrentVersion\AppModel\Repository\Packages\Claude_*
• Ran wsreset.exe to clear Windows Store cache
• Used takeown and icacls to take ownership of WindowsApps folders — access still denied
• Used robocopy /purge to empty WindowsApps folders — files removed but root folders still undeletable
• Tried DISM /Remove-ProvisionedAppxPackage — Error 2
• Deleted HKLM:\SYSTEM\CurrentControlSet\Services\CoworkVMService registry key — but installer still reports the service as conflicting after reboot

Key log lines:

WARNING: CoworkVMService already exists (potential conflict)
Conflicting service: true
WARNING: failed to remove conflicting service: could not open CoworkVMService: Access Denied
MSIX installation failed: AddPackage failed: AddPackage failed with HRESULT 0x80073CF6

Additional context

Two leftover folders remain in C:\Program Files\WindowsApps\ that cannot be deleted even with full admin rights:

• Claude_1.10628.2.0_x64__pzs8sxrjxfjjc
• Claude_1.11187.1.0_x64__pzs8sxrjxfjjc

Cowork was actively used with a personal Second Brain setup — restoring full desktop app functionality with Cowork is critical for my workflow.

Full log file attached.

Error Messages/Logs

Steps to Reproduce

Steps to reproduce

1. Download Claude Setup.exe from claude.ai
2. Run installer (with or without administrator privileges)
3. Installer downloads and verifies MSIX successfully
4. Installation fails at AddPackage step

What I tried

• Restarted the computer multiple times
• Stopped CoworkVMService via Task Manager and PowerShell (sc.exe stop)
• Removed Claude AppX packages via Get-AppxPackage *Claude* | Remove-AppxPackage -AllUsers
• Deleted registry key HKCU:\Software\Classes\Local Settings\Software\Microsoft\Windows\CurrentVersion\AppModel\Repository\Packages\Claude_*
• Ran wsreset.exe to clear Windows Store cache
• Used takeown and icacls to take ownership of WindowsApps folders — access still denied
• Used robocopy /purge to empty WindowsApps folders — files removed but root folders still undeletable
• Tried DISM /Remove-ProvisionedAppxPackage — Error 2
• Deleted HKLM:\SYSTEM\CurrentControlSet\Services\CoworkVMService registry key — but installer still reports the service as conflicting after reboot

Key log lines:

WARNING: CoworkVMService already exists (potential conflict)
Conflicting service: true
WARNING: failed to remove conflicting service: could not open CoworkVMService: Access Denied
MSIX installation failed: AddPackage failed: AddPackage failed with HRESULT 0x80073CF6

Additional context

Two leftover folders remain in C:\Program Files\WindowsApps\ that cannot be deleted even with full admin rights:

• Claude_1.10628.2.0_x64__pzs8sxrjxfjjc
• Claude_1.11187.1.0_x64__pzs8sxrjxfjjc

Cowork was actively used with a personal Second Brain setup — restoring full desktop app functionality with Cowork is critical for my workflow.

Full log file attached.

Claude Model

None

Is this a regression?

Yes, this worked in a previous version

Last Working Version

No response

Claude Code Version

N/A

Platform

Anthropic API

Operating System

macOS

Terminal/Shell

Terminal.app (macOS)

Additional Information

No response

[github-actions]

Found 3 possible duplicate issues:

1. [BUG] Claude Desktop Windows installer fails with AddPackage HRESULT 0x80073CF6 after an earlier "successful" install left the package in an inconsistent state #49917
2. [BUG] Claude Desktop update fails with 0x80073CF6 when CoworkVMService is running (Windows) #49655
3. [BUG] Windows: MSIX updates leave orphaned package versions; Deleted-folder cleanup fails with ERROR_OPLOCK_NOT_GRANTED (0x12C), blocking all installs with 0x80073CF6 #66017

This issue will be automatically closed as a duplicate in 3 days.

• If your issue is a duplicate, please close it and 👍 the existing issue instead
• To prevent auto-closure, add a comment or 👎 this comment

🤖 Generated with Claude Code

[solrahel95-ship-it]

I'm hitting this same issue on Windows [10.0.26200], x64, Windows Core edition. Package: Claude_1.24012.9.0_x64__pzs8sxrjxfjjc.

Ran a full diagnostic cycle: confirmed elevation was genuine (Is elevated: true), package consistently shows NeedsRemediation after install/launch even though AppXDeploymentServer log shows the install itself completing successfully. Windows Repair and Reset both fail ("couldn't repair/reset this app"). CoworkVMService starts cleanly per its own log but gets stopped ~10-40s later before the app configures it — no crash dump or Application Error event generated. Ran the official Cowork Readiness Check: machine reports fully ready, and I independently confirmed via secedit that the VM service account (S-1-5-83-0) has correct SeServiceLogonRight with no deny entry — ruling out environment/config causes.

Full details attached. Also opened support ticket (Conversation ID 215475247858468) with no resolution yet.

claude-desktop-install-issue-report (1).txt