MSIX installation fails with HRESULT 0x80073CFF after previous uninstall — Windows 11 Pro (26200)

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?

Claude Desktop fails to install with HRESULT 0x80073CFF at the AddPackage step. The app was previously installed and working, then the window went blank. After uninstalling and attempting to reinstall, the installer downloads the MSIX successfully, validates the Authenticode signature, but fails every time when registering the MSIX package via AddPackage.

The error persists across multiple reinstall attempts, running as administrator, enabling Developer Mode, clearing AppData folders, and removing registry entries.

What Should Happen?

Claude Desktop should install successfully and launch normally, as it did before the previous installation was removed.

Error Messages/Logs

2026/05/11 09:14:42.236641 === Claude Setup 5095e7dddcba4ca974d351ee397e17d204814f07 started ===
2026/05/11 09:14:42.236641 Windows edition: Professional
2026/05/11 09:14:42.237846 Windows version: 10.0.26200
2026/05/11 09:14:42.237846 Native arch: x64
2026/05/11 09:14:42.237846 Elevation type: Full
2026/05/11 09:14:42.237846 Is elevated: true
2026/05/11 09:14:42.237846 Sideloading enabled: true
2026/05/11 09:14:42.237846 S Mode: false
2026/05/11 09:14:42.237846 Conflicting service: false
2026/05/11 09:14:52.948577 Squirrel process prefix: c:\users\luis.pulido\appdata\local\anthropicclaude\
2026/05/11 09:14:52.967323 Checking for existing Claude MSIX packages...
2026/05/11 09:14:53.059222 Extracted family name from MSIX manifest: Claude_pzs8sxrjxfjjc
2026/05/11 09:14:53.059222 Standard install (not split-account), using AddPackage
2026/05/11 09:14:53.059222 Installing via AddPackage (current-user)...
2026/05/11 09:14:54.317931 MSIX installation failed: AddPackage failed: AddPackage failed with HRESULT 0x80073CFF

Steps to Reproduce

1. Had Claude Desktop previously installed and working
2. App window went completely blank
3. Uninstalled Claude Desktop
4. Downloaded latest Claude Setup and ran as administrator
5. Installer downloads and verifies MSIX successfully
6. Fails at AddPackage step with 0x80073CFF

Claude Model

None

Is this a regression?

Yes, this worked in a previous version

Last Working Version

Unknown — the app was working on a previous installation but the exact version number was not recorded before uninstalling.

Claude Code Version

1.6608.2 (Setup SHA: 5095e7dddcba4ca974d351ee397e17d204814f07)

Platform

Anthropic API

Operating System

Windows

Terminal/Shell

Terminal.app (macOS)

Additional Information

Windows build 10.0.26200 appears to be a recent/Insider build. It's possible MSIX AddPackage behavior differs from stable releases. A ghost/orphaned package registration from the previous installation may be blocking the new install despite not appearing in Get-AppxPackage results.