[BUG] [claude deskop] The `--user-data-dir` parameter has no effect on child processes.

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?

<img width="1241" height="192" alt="Image" src="https://github.com/user-attachments/assets/a030d80b-47be-4e18-b074-53277ebfbff3" />

When using claude.exe --user-data-dir=test3p, I noticed that data was not being created for the corresponding workspace as expected. Task Manager revealed that the --user-data-dir argument for the child processes was pointing to the default location rather than d:\test3p. This issue did not exist in older versions; however, I hadn't updated the software for a long time until today. Please investigate this issue—thank you.

What Should Happen?

when update to 1.44121.4

Error Messages/Logs

Steps to Reproduce

1. claude.exe --user-data-dir=d:\test3p
2. Check if the working directory is normal.

Claude Model

None

Is this a regression?

Yes, this worked in a previous version

Last Working Version

_No response_

Claude Code Version

Claude 1.44121.4 (0d57a2) 2026-09-02T23:50:20.000Z

Platform

Other

Operating System

Windows

Terminal/Shell

PowerShell

Additional Information

_No response_