[BUG] Windows Desktop App - spawn UNKNOWN error on LocalSessions start

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 Code Desktop app throws this error when trying to start any new session:

Error invoking remote method '$eipc_message$_3bfb63fe-8b05-4970-928b-b5015a203690_$_claude.web_$_LocalSessions_$_start': Error: spawn UNKNOWN

Environment:

• OS: Windows 11
• Claude Code version: 2.1.87
• Installed via: official installer (install.ps1)
• Node version: v24.14.0
• Git version: 2.53.0.windows.2

What I tried:

• Reinstalled via npm and official installer
• Set execution policy to RemoteSigned
• Added Git Bash path to settings.json
• Cleared session folders
• Full computer restart

What works:

• Terminal version (claude --version) works fine
• Claude Code CLI launches in terminal
• Desktop app loads and shows preview but cannot send new messages

What doesn't work:

• Cannot start or continue any session from the Desktop app
• Error appears immediately when trying to type/send in the Desktop chat

This started after a forced computer restart. Please fix — I'm using this for active client work and am on a deadline.

What Should Happen?

<img width="1837" height="1116" alt="Image" src="https://github.com/user-attachments/assets/5630c0d4-953f-4652-bffb-a9dd3ae1d56c" />

Error Messages/Logs

Error invoking remote method '$eipc_message$_3bfb63fe-8b05-4970-928b-b5015a203690_$_claude.web_$_LocalSessions_$_start': Error: spawn UNKNOWN

Steps to Reproduce

1. Open Windows PowerShell
2. Launch Claude Code Desktop app (v2.1.87) on Windows 11
3. Navigate to the Code tab
4. Attempt to start a new session or continue an existing session
5. Error immediately appears in top right corner:

Error invoking remote method '$eipc_message$_3bfb63fe-8b05-4970-928b-b5015a203690_$_claude.web_$_LocalSessions_$_start': Error: spawn UNKNOWN

Additional context:

• Issue started after a forced computer restart after my claude desktop app froze, after I updated it to the new version.
• Claude Code CLI works fine in terminal (claude --version returns 2.1.87)
• Git is installed (v2.53.0.windows.2) and Git Bash path is set in settings.json
• Desktop app loads and shows website preview but cannot send or receive new messages
• Tried: reinstalling via npm and official installer, setting execution policy, adding Git Bash path to settings.json, clearing session folders, full restart
• Last working version: 2.1.86

Claude Model

Not sure / Multiple models

Is this a regression?

Yes, this worked in a previous version

Last Working Version

Last working version: 2.1.86 Broke after auto-update to 2.1.87

Claude Code Version

2.1.87

Platform

Anthropic API

Operating System

Windows

Terminal/Shell

PowerShell

Additional Information

My claude chat and cowork are both working. my claude code is not. its giving me the error message in a new session. but in my other sessions, it lets me type a message and hit send, but the message doesn't show up in the chat, and it doesn't do anything. Please help. i have clients i have to do work for, as well as working on coding my website, and i cannot continue any of these tasks.