[BUG] Windows Desktop Installer fails with HRESULT 0x80073CF6 - windows.firewall extension Access Denied 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?

Here are some of the issues. Every 'newer' Claude Desktop for Windows installer failed. Was working with Claude to diagnose the issue without resolution. I was ultimately able to install desktop application, but ONLY after I used a much older version of the installer (3-5 months old). See issues below:

• Windows version: 10.0.26200 (Windows 11 Pro)
• All newer installers (Claude Setup_2 through _4) failed with the firewall extension error
• Bitdefender Total Security was installed but uninstalling it did not resolve the issue
• SFC and DISM showed no corruption
• The older bundled 146MB installer (Claude Setup.exe) succeeded as a workaround
• The exact error: error 0x80070005: While processing the request, the system failed to register the windows.firewall extension due to the following error: Access is denied

Attaching ClaudeSetup.log file for your use.

ClaudeSetup.log

What Should Happen?

Claude 'should' have installed without errors, but could not get that to happen with any 'newer' version of Claude Desktop.

Error Messages/Logs

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

error 0x80070005: While processing the request, the system failed to register 
the windows.firewall extension due to the following error: Access is denied.

Steps to Reproduce

1. Download the latest Claude Desktop installer (Claude Setup.exe) from claude.ai
2. Run the installer as Administrator on Windows 11 Pro (version 10.0.26200)
3. Installer downloads the MSIX, verifies signature successfully, then fails

during AddPackage with HRESULT 0x80073CF6

1. Error occurs consistently regardless of:

• Whether antivirus (Bitdefender Total Security) is installed or uninstalled
• Whether Windows Firewall is enabled or disabled
• Whether SFC /scannow and DISM /RestoreHealth are run first
• Whether firewall registry permissions are reset to defaults
• Whether the installer is run as Administrator or as normal user

1. Workaround: An older bundled installer (146MB self-contained version)

installs successfully, suggesting the newer MSIX-based installer's
firewall extension registration step is incompatible with certain
Windows configurations

Claude Model

None

Is this a regression?

I don't know

Last Working Version

_No response_

Claude Code Version

2.1.71

Platform

Anthropic API

Operating System

Windows

Terminal/Shell

PowerShell

Additional Information

Claude Desktop installer bug, not a Claude Code issue.