Cowork "Download failed" on macOS Tahoe 26.4 — workspace fails to start after reinstall

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?

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

OS: macOS Tahoe 26.4
Mac: MacBook Pro 16-inch Nov 2023, Apple M3 Pro, 18GB RAM

Cowork fails to start and shows the "Download failed" error. The error persists even after multiple reinstall attempts. Regular Claude Chat mode works fine, only Cowork is affected. Internet connection is working normally, no VPN in use.

What Should Happen?

Cowork workspace should start successfully without any "Download failed" error after reinstall.

Error Messages/Logs

"Failed to start Claude's workspace — Download failed. Check your internet connection and try again."

Steps to Reproduce

1. Open Claude desktop app on macOS Tahoe 26.4
2. Navigate to Cowork mode
3. Observe the error: "Failed to start Claude's workspace — Download failed. Check your internet connection and try again."
4. Attempted fix: Restarted the computer → error persists
5. Attempted fix: Clicked "Reinstall workspace" twice → error persists
6. Attempted fix: Ran rm -rf ~/Library/Application\ Support/Claude/claude-code-vm in Terminal → error persists
7. Attempted fix: Used "Delete Cowork VM Bundle and Restart" from Help → Troubleshooting → error persists after all attempts

Note: Internet connection is working normally, no VPN in use. Regular Claude Chat mode works fine.

Claude Model

None

Is this a regression?

Yes, this worked in a previous version

Last Working Version

_No response_

Claude Code Version

latest

Platform

Anthropic API

Operating System

macOS

Terminal/Shell

Terminal.app (macOS)

Additional Information

• MacBook Pro 16-inch Nov 2023, Apple M3 Pro, 18GB RAM
• macOS Tahoe 26.4
• Internet connection working normally, no VPN in use
• Regular Claude Chat mode works fine, only Cowork is affected
• All standard troubleshooting steps from Help → Troubleshooting have been exhausted