Claude Desktop installation fails with HRESULT 0x80073CF6 on Windows 11 Pro

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?

System:

• Windows 11 Pro, Build 26200
• Intel i5-14600K, 48GB RAM
• x64-based PC, Gigabyte Z790 Eagle AX

Problem:
Installation fails at the MSIX package registration step with error:
"AddPackage failed with HRESULT 0x80073CF6"

Steps taken:

1. Removed old Claude package via Get-AppxPackage claude | Remove-AppxPackage
2. Deleted all leftover Claude folders from LocalAppData
3. Confirmed CoworkVMService does not exist
4. Restarted PC
5. Downloaded fresh installer from claude.com/download
6. Ran as Administrator
7. Same error persists every time

Expected: Claude Desktop installs successfully
Actual: Installation fails with HRESULT 0x80073CF6

What Should Happen?

Claude Desktop should install successfully on Windows 11 Pro

Error Messages/Logs

Installation failed: AddPackage failed: AddPackage failed with HRESULT 0x80073CF6

Steps to Reproduce

1. Download ClaudeSetup.exe from claude.com/download
2. Run as Administrator on Windows 11 Pro Build 26200
3. Installation fails with HRESULT 0x80073CF6

Claude Model

None

Is this a regression?

Yes, this worked in a previous version

Last Working Version

_No response_

Claude Code Version

Claude.ai

Platform

Anthropic API

Operating System

Windows

Terminal/Shell

PowerShell

Additional Information

Attempted full cleanup via PowerShell before reinstalling:

• Get-AppxPackage claude | Remove-AppxPackage (ran successfully)
• Deleted LocalAppData Claude folders
• CoworkVMService confirmed not present
• Fresh installer downloaded, same error persists