Bash tool: EUNKNOWN uv_spawn error on Windows (all shells fail)

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 happened?
Every Bash command fails with: EUNKNOWN: unknown error, uv_spawn
Even a simple echo test does not work.

Steps to reproduce:

1. Use Claude Code VS Code extension on Windows.
2. Run any Bash command, e.g. echo test.
3. Error appears immediately.

Attempted fixes (all produce the same uv_spawn error):

• Set shellPath to PowerShell
• Set shellPath to Git Bash
• Set shellPath to cmd.exe
• Reloaded VS Code after each change.

Environment checks (all clean):

• Group Policy: "Prevent access to command prompt" -> Not Configured
• Software Restriction Policies -> None defined
• Windows Defender Exploit Protection -> No VS Code / Claude entries
• Protection history -> No relevant blocks
• Third-party antivirus -> None installed

Expected behavior:
Bash commands should execute normally.

Environment:

• OS: Windows 10/11
• Claude Code: VS Code extension (latest)
• Shell: tested PowerShell, Git Bash, cmd

What Should Happen?

Bash commands should execute normally without throwing uv_spawn errors.

Error Messages/Logs

EUNKNOWN: unknown error, uv_spawn

Steps to Reproduce

Open Claude Code in VS Code on Windows.

Run any Bash command, e.g. echo test.

Immediately see error.

Claude Model

Other

Is this a regression?

I don't know

Last Working Version

_No response_

Claude Code Version

VS Code extension v1.0.70

Platform

Anthropic API

Operating System

Windows

Terminal/Shell

VS Code integrated terminal

Additional Information

_No response_