[BUG] Cowork: "Download failed" error after files validated successfully (Windows 11 Home, MSIX install)

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?

Every Cowork session fails with "Failed to start Claude's workspace — Download failed. Check your internet connection and try again."

Environment:

• OS: Windows 11 Home
• Claude Desktop version: 1.8089.1.0 (MSIX, installed from claude.com/download)
• Hardware: Dell laptop, Intel/AMD x64
• VirtualMachinePlatform: Enabled
• HypervisorPlatform: Enabled
• CoworkVMService: Running

Diagnostic findings:

• Network connectivity verified (storage.googleapis.com:443 OK, api.anthropic.com:443 OK)
• Disk space: 755 GB free of 932 GB
• VM bundle files all present and checksum-validated
• No VPN adapters installed
• Tried: full uninstall + reinstall, delete claudevm.bundle, delete warm folder, delete .auto_reinstall_attempted markers, enable HypervisorPlatform feature, reboot

Log excerpt (cowork_vm_node.log) showing the contradictory "All files ready → Download failed" sequence:
[Paste the section from your log starting around 21:50:08 through 21:50:09, showing the four "checksum validated" lines, the "All files ready" line, and the immediate "download_and_sdk_prepare failed" line]

What Should Happen?

Cowork should start successfully. If all VM bundle files are present and checksum-validated, the workspace should launch without reporting a "Download failed" error.

Error Messages/Logs

Log excerpt from cowork_vm_node.log (around 21:50:08 through 21:50:09):

[Four "checksum validated" lines showing all VM bundle files validated OK]
[Line showing "All files ready"]
[Immediate next line showing "download_and_sdk_prepare failed"]

Full log files attached:
- C:\Users\Dell\AppData\Roaming\Claude\logs\cowork_vm_node.log
- C:\ProgramData\Claude\Logs\cowork-service.log

Error message shown in UI:
"Failed to start Claude's workspace — Download failed. Check your internet connection and try again."

Steps to Reproduce

1. Open Claude Desktop (version 1.8089.1.0, MSIX install on Windows 11 Home)
2. Attempt to start a Cowork session
3. Observe the error: "Failed to start Claude's workspace — Download failed. Check your internet connection and try again."

Note: This started failing sometime between May 16-18, 2026 despite previously working. All VM bundle files are present and checksum-validated per the logs.

Claude Model

None

Is this a regression?

Yes, this worked in a previous version

Last Working Version

Working as of May 16, 2026

Claude Code Version

1.8089.1.0 (MSIX)

Platform

Anthropic API

Operating System

Windows

Terminal/Shell

Windows Terminal

Additional Information

• Cowork was working through May 16, 2026. Stopped working sometime between May 16-18, 2026.
• Hardware: Dell laptop, Intel/AMD x64
• VirtualMachinePlatform: Enabled
• HypervisorPlatform: Enabled
• CoworkVMService: Running
• Log files attached: cowork_vm_node.log and cowork-service.log