[BUG] Claude Desktop installation fails with HRESULT 0x80073CFF on Windows 11 Home

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 installer fails at the MSIX AddPackage step with HRESULT 0x80073CFF on Windows 11 Home (Core). The log shows AllowAllTrustedApps not found — this registry key is absent on Windows 11 Home and cannot be configured via Group Policy, which is not available on the Home edition.

What Should Happen?

Claude Desktop should install successfully on Windows 11 Home without requiring Group Policy configuration, which is not available on the Home edition.

Error Messages/Logs

AllowAllTrustedApps not found (sideloading assumed enabled)
Windows edition: Core
MSIX installation failed: AddPackage failed: AddPackage failed with HRESULT 0x80073CFF

Steps to Reproduce

1. Use a machine with Windows 11 Home (Core), build 26200
2. Download ClaudeSetup.exe from claude.ai/download
3. Run the installer
4. Installer fails with HRESULT 0x80073CFF

Claude Model

None

Is this a regression?

Yes, this worked in a previous version

Last Working Version

_No response_

Claude Code Version

N/A - Claude Desktop installer

Platform

Anthropic API

Operating System

macOS

Terminal/Shell

Terminal.app (macOS)

Additional Information

This is a Claude Desktop installer issue, not Claude Code.
Attempted fixes: enabled Developer Mode, manually added AllowAllTrustedApps registry key via PowerShell, cleared AppData. All failed.
Related issues: #53634, #60319, #58174

ClaudeSetup.log