[BUG] Claude Desktop installation fails - Administrator access required (Cowork) on Windows 11 Pro Build 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?
What's Wrong?
Claude Desktop installation fails on Windows 11 Pro. The installer first failed with an MSIX AddPackage error (HRESULT 0x80073CFF). After enabling sideloading via registry (AllowAllTrustedApps and AllowDevelopmentWithoutDevLicense set to 1), the error changed to an administrator access error, and the installation still does not complete successfully.
Error messages encountered:
- First attempt:
"Installation failed: AddPackage failed: AddPackage failed with HRESULT 0x80073CFF"
- After enabling sideloading:
"Administrator access is required to install Claude with full features. You can try again or install without Cowork."
Environment:
- Windows edition: Windows 11 Pro
- Version: 25H2
- OS build: 26200.8655
- Experience: Windows Feature Experience Pack 1000.26100.315.0
- Installed on: 06/10/2024
Steps taken (all attempted):
- Ran the installer normally — failed with HRESULT 0x80073CFF
- Enabled sideloading via PowerShell (Administrator):
reg add "HKLM\SOFTWARE\Microsoft\Windows\CurrentVersion\AppModelUnlock" /t REG_DWORD /v AllowAllTrustedApps /d 1 /f
reg add "HKLM\SOFTWARE\Microsoft\Windows\CurrentVersion\AppModelUnlock" /t REG_DWORD /v AllowDevelopmentWithoutDevLicense /d 1 /f
- Rebooted and retried the installer — error changed to the administrator access / Cowork error above
- Attempted to run the installer as administrator (right-click → Run as administrator)
Expected behavior:
Claude Desktop should install successfully with full features (including Cowork) on Windows 11 Pro with administrator rights available.
Actual behavior:
Installation fails and prompts to either retry or install without Cowork, even when run with administrator rights.
Diagnostic log location:
C:\Users\Dell\AppData\Local\Temp\ClaudeSetup.log
(log file attached)
What Should Happen?
Claude Desktop should install successfully with full features, including Cowork, on Windows 11 Pro (Build 26200.8655) when the user has administrator rights and sideloading is enabled. The installer should not fail at the AddPackage step, and it should not require additional administrator prompts beyond the standard UAC elevation already granted when running the installer as administrator.
If full installation with Cowork cannot succeed due to a system limitation, the "install without Cowork" fallback option should work reliably and complete the installation of the core Claude Desktop app.
Error Messages/Logs
Steps to Reproduce
- Download the Claude Desktop installer from https://claude.com/download on a Windows 11 Pro (Build 26200.8655) machine.
- Run the installer.
- Observe the installation fails with: "Installation failed: AddPackage failed: AddPackage failed with HRESULT 0x80073CFF"
- Open PowerShell as Administrator and enable sideloading:
reg add "HKLM\SOFTWARE\Microsoft\Windows\CurrentVersion\AppModelUnlock" /t REG_DWORD /v AllowAllTrustedApps /d 1 /f
reg add "HKLM\SOFTWARE\Microsoft\Windows\CurrentVersion\AppModelUnlock" /t REG_DWORD /v AllowDevelopmentWithoutDevLicense /d 1 /f
- Reboot the machine.
- Run the installer again, this time right-clicking and selecting "Run as administrator."
- Approve the UAC prompt.
- Observe the installation now fails with: "Administrator access is required to install Claude with full features. You can try again or install without Cowork."
Claude Model
None
Is this a regression?
Yes, this worked in a previous version
Last Working Version
_No response_
Claude Code Version
N/A — this issue is about the Claude Desktop installer, which has not successfully installed. Claude Code CLI is not installed on this machine.
Platform
Anthropic API
Operating System
macOS
Terminal/Shell
Terminal.app (macOS)
Additional Information
_No response_