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Windows: chat fails with "UNC paths are not supported. Defaulting to Windows directory." when using WSL paths #716
Description
Activity
Another +1 from Windows + WSL with the Codex provider specifically.
Repro details from my setup:
- Project opened from a WSL path like
\\wsl.localhost\Ubuntu\home\ubuntu\Projects - Codex CLI installed inside WSL and works there
- The desktop app appears to launch the provider/version check through Windows
cmd.exeinstead of inside WSL
Observed errors in the app:
Codex CLI is installed but failed to run. 'codex' is not recognized as an internal or external command, operable program or batch file.\n-Codex CLI version check failed. \\wsl.localhost\Ubuntu\home\ubuntu\Projects CMD.EXE was started with the above path as the current directory. UNC paths are not supported. Defaulting to Windows directory. The system cannot find the path specified.\n\nThis makes the current Windows app path/provider flow incompatible with WSL-hosted workspaces even when Codex itself is correctly installed in Linux.\n\nA robust fix would be first-class WSL execution support, or at minimum detecting WSL UNC workspaces and failing with a clear actionable message instead of attempting a Windows-side launch in a UNC cwd.
- Project opened from a WSL path like
@Shivam8584 @MansGullberg , try the latest version of both codex and t3code and tell me if it's still happening. !!
Reacted by Måns Gullberg@shivamhwp @MansGullberg , try the latest version of both codex and t3code and tell me if it's still happening. !!
Still happening. Codex app works fine, not T3 Code v 0.14
@shivamhwp Found a hackable workaround for now in v 0.15:
this file on desktop: codex-wsl.cmd:
@echo off setlocal set "WSL_EXE=%SystemRoot%\System32\wsl.exe" set "WSL_DISTRO=Ubuntu" set "WSL_USER=redacted" set "CODEX_WSL_PATH=/mnt/c/Users/redacted/.codex/bin/wsl/codex" if not exist "%WSL_EXE%" ( echo Failed to find wsl.exe at "%WSL_EXE%". exit /b 1 ) "%WSL_EXE%" -d %WSL_DISTRO% -u %WSL_USER% --shell-type login "%CODEX_WSL_PATH%" %* exit /b %ERRORLEVEL%
Codex binary path set in t3 code: C:\Users\redacted\Desktop\codex-wsl.cmd
CODEX_HOME path set in t3 code: \wsl.localhost\Ubuntu\home\redacted.codex
--
Now the desktop app can authenticate and talk to Codex. However, checkpoint capture fails because the app appears to use Windows Git on the WSL UNC repo path, and Windows Git does not trust that repo by default. So I ran: git config --global --add safe.directory "*" in powershell and now all warnings are gone. 👍
--
Last problem, toggling terminal drawer fails because of UNC path and defaults back into windows as cmd. Would be nice to be able to select terminal preferences in the settings.
- added a commit that references this issue
on Apr 23, 2026
Summary
On Windows, chat fails when the app is used with WSL-based paths. I get:
UNC paths are not supported. Defaulting to Windows directory.This appears to be caused by the app or one of its spawned processes using a UNC WSL path such as:
\\wsl.localhost\Ubuntu\home\<user>\...instead of a normal Windows drive path.
Environment
\\wsl.localhost\Ubuntu\home\<user>\...What I expected
Chat should work when the project or Codex-related files are in WSL, or the app should convert the WSL path to a supported working directory before spawning the shell/process.
What actually happens
The app shows:
UNC paths are not supported. Defaulting to Windows directory.After that, chat/session behavior breaks because the process is no longer running in the intended project directory.
Reproduction
\\wsl.localhost\Ubuntu\home\<user>\projectUNC paths are not supported. Defaulting to Windows directory.Notes
I also tried moving
CODEX_HOMEto a normal Windows path (C:\Users\<user>\.codex) so it would not point into WSL anymore.That did not resolve the problem, which suggests the failing UNC path is likely the workspace/current working directory or another path the app passes into the spawned shell, not just
CODEX_HOME.Possible root cause
This looks like a Windows
cmd.exe/ process-launch limitation with UNC working directories. If the app starts a shell/process with a current directory like\\wsl.localhost\..., Windows falls back toC:\Windowsinstead.Suggested fix
This issue report was generated by GPT-5.4 on High running in the Codex app on Windows in a WSL environment.