[BUG] Bash tool fails with EINVAL on Windows - cannot open task output file

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?

Details to include:

• Windows 11 Pro 10.0.26200
• PowerShell 7.5.4
• Claude Code 2.1.53
• Error: EINVAL: invalid argument, open 'C:\Temp\claude\...\tasks\<id>.output'
• The directory exists and is writable (other tools like Write work fine at the same path)
• Tried: changing TEMP path, changing shell config, rebooting

this was working properly until, during it's examination of work items, it crashed the Operating System. Upon the restart these errors persist. Even when creating a new conversation.

What Should Happen?

claude should be able to read the files it creates correctly.

Error Messages/Logs

Bash(echo hello)
  ⎿  Error: EINVAL: invalid argument, open 'C:\Temp\claude\C--repos-[redacted]\tasks\brr76mx6j.output'

Steps to Reproduce

I don't know because it would require claude to crash the OS

Claude Model

Opus

Is this a regression?

Yes, this worked in a previous version

Last Working Version

_No response_

Claude Code Version

2.1.53

Platform

Anthropic API

Operating System

Windows

Terminal/Shell

PowerShell

Additional Information

_No response_