[BUG] Cowork installation fails with HRESULT 0x80073CFF on Windows 11 Pro - installer cannot remove orphaned package/service
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 Cowork is completely broken on Windows 11 Pro. The installer fails repeatedly with HRESULT 0x80073CFF on every reinstall attempt. The stale Claude_1.1.3189.0 package cannot be removed (HRESULT 0x80073CFA), and the orphaned CoworkVMService cannot be removed even with elevation (Access denied). This creates an unrecoverable installation loop. Claude.ai web and Claude Code work fine - only Cowork is broken.
Even when the service is running, cowork-service.log shows the client never issues a "Start VM" command, hcsdiag list returns empty, and Get-HnsNetwork shows no Cowork network is created.
Logs attached: ClaudeSetup.log and cowork-service.log
ClaudeSetup.log
cowork-service.log
What Should Happen?
Installer should successfully remove the old package and conflicting service, then install the new version. Cowork workspace should boot.
Error Messages/Logs
Steps to Reproduce
- Download Claude Setup from claude.ai/download
- Run as administrator
- Installer fails with HRESULT 0x80073CFF
- Error dialog: "Administrator access is required to install Claude with full features"
- Repeats on every attempt
Claude Model
None
Is this a regression?
Yes, this worked in a previous version
Last Working Version
_No response_
Claude Code Version
n/a
Platform
Anthropic API
Operating System
macOS
Terminal/Shell
Terminal.app (macOS)
Additional Information
- OS: Windows 11 Professional, 10.0.26200, x64
- Plan: Max
- Hyper-V: Enabled, hypervisor loaded
- HypervisorPlatform: Enabled
- VirtualMachinePlatform: Enabled
- hypervisorlaunchtype: Auto
- vmcompute, vmms: Running
- BIOS virtualization: Enabled
- Sideloading: Enabled
- No VMware/VirtualBox
- Possibly related: #25663, #37312, #54011, #56566
3 Comments
Found 3 possible duplicate issues:
This issue will be automatically closed as a duplicate in 3 days.
🤖 Generated with Claude Code
NOT a duplicate. Please review carefully before closing.
I checked #57744, #51132, #57035 — none of them match my specific failure mode:
Attaching full ClaudeSetup.log and cowork-service.log for engineering review.
This is a paying Max plan user. Please escalate to a human engineer. The chatbot/bot triage has not been able to resolve this after extensive diagnostics. Auto-closing this without human review would be unacceptable.
This issue has been automatically locked since it was closed and has not had any activity for 7 days. If you're experiencing a similar issue, please file a new issue and reference this one if it's relevant.