[B[BUG] Cowork Windows - RPC error -1: virtiofs/Plan9 mount fails after brief use

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?
Cowork on Windows fails with: RPC error -1: failed to ensure virtiofs mount: Plan9 mount failed: bad address

The error occurs repeatedly. Cowork works briefly after restarting Claude Desktop, then breaks again after a short time. Restarting does not permanently fix it.

Steps to reproduce:

1. Open Claude Desktop on Windows
2. Open Cowork tab
3. Run any task
4. Cowork works briefly then crashes with the error above
5. Restarting Claude Desktop temporarily fixes it but error returns

What I tried:

• Restarting Claude Desktop
• Killing all claude.exe processes in Task Manager
• Switching workspace folder from Desktop to a plain folder (C:\Users\User\COWORK)
• Running wsl --shutdown (WSL not installed)

System:

• OS: Windows 11 Home
• Product: Cowork on Claude Desktop (not Claude Code CLI)
• Subscription: Max plan
• WSL: Not installed

What Should Happen?

the system should be stable and not crash or become inactive intermittently

Error Messages/Logs

RPC error -1: failed to ensure virtiofs mount: Plan9 mount failed: bad address

Steps to Reproduce

not sure this possible as im ruining from my personal desktop

Claude Model

Sonnet (default)

Is this a regression?

I don't know

Last Working Version

_No response_

Claude Code Version

1.14010 (da63f3

Platform

Anthropic API

Operating System

Windows

Terminal/Shell

Terminal.app (macOS)

Additional Information

_No response_