[BUG] Claude Desktop MSIX Installation Fails with HRESULT 0x80073CF6 on Windows 11

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?

Hello Anthropic Support Team,

I am experiencing a critical installation issue with Claude Desktop on Windows 11 after the latest update. I would like to report this bug.

--- SYSTEM INFO ---
OS: Windows 11 (Core Edition)
Windows Version: 10.0.26200
Architecture: x64

--- PROBLEM DESCRIPTION ---
After updating Claude Desktop, the application started crashing immediately on launch. When I tried to reinstall, the installation fails with the following error:

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

The installer shows: "Administrator access is required to install Claude with full features. You can try again or install without Cowork."

--- STEPS I HAVE TRIED ---

• Removed existing Claude AppX packages via PowerShell
• Deleted CoworkVMService (service was not found)
• Cleared %AppData%\Claude and %LocalAppData%\Claude folders
• Reset Windows Store cache with wsreset.exe
• Enabled Developer Mode in Windows Settings
• Ran installer as Administrator multiple times
• Restarted the computer

--- LOG EXCERPT ---
WARNING: CoworkVMService already exists (potential conflict)
WARNING: failed to remove conflicting service: could not open CoworkVMService: Access is denied.
MSIX installation failed: AddPackage failed: AddPackage failed with HRESULT 0x80073CF6

Full log file: C:\Users\ender\AppData\Local\Temp\ClaudeSetup.log
(I can attach the full log file upon request.)

--- CURRENT STATUS ---
Claude Desktop is partially working — Chat tab functions normally, but the Code tab causes the application to crash immediately.

Please investigate this issue. I am happy to provide any additional information or logs needed.

Thank you,
Ender

ClaudeSetup.log

What Should Happen?

Claude Desktop should install successfully with full features including the Code tab without any MSIX registration errors.

Error Messages/Logs

Steps to Reproduce

1. Download Claude Desktop installer from claude.com/download
2. Run installer as Administrator
3. Installer downloads MSIX and attempts to register it
4. Installation fails with HRESULT 0x80073CF6
5. Code tab crashes immediately when clicked even after partial install

Claude Model

Sonnet (default)

Is this a regression?

Yes, this worked in a previous version

Last Working Version

_No response_

Claude Code Version

2.1.92

Platform

Anthropic API

Operating System

Windows

Terminal/Shell

PowerShell

Additional Information

_No response_