Exact error
Match the message before using the fix
Unable to spawn codex-linux-sandbox because it doesn't exist on the filesystem (ENOENT: No such file or directory)Failed to create unified exec processQuick answer
Start here
Quit Codex completely and reopen it so the app creates a fresh temporary sandbox helper path. That restored commands in the original report. If the helper is still missing after restart, run the repository directly in WSL with the WSL Codex CLI or repair the app; later reports show restart is not universal.
Diagnosis
Why it happens
- A resumed task can retain a temporary helper path that no longer exists.
- An update or cleanup can remove the old helper directory while the app still references it.
Safest first
Fixes, in order
Fully quit and restart Codex
Applies when: First step when the error path contains a temporary arg0/helper directory
The original reporter confirmed that a full app restart generated a new helper directory.
- Save your work.
- Quit all Codex windows and confirm the app process has ended.
- Start Codex again.
- Create a new task and run a harmless command.
Expected: The error references a new helper path and the command starts normally.
Run the repository natively inside WSL
Applies when: Use when restart does not regenerate the helper
Keeping the repository and CLI in WSL avoids the Desktop bridge while the app-specific issue is unresolved.
- Open the WSL distribution.
- Use a repository stored in the WSL filesystem where possible.
- Install/run the current Codex CLI in WSL.
- Start a new task there.
Expected: Codex uses the Linux environment without the missing bridged helper.
Verification
Prove the fix worked
- Run a harmless shell command in a new task.
- Confirm the helper path exists for the lifetime of the session.
- Restart once more and verify a new session still works.
Escalation
If it still fails
- Record Codex app/CLI version, WSL distribution, repository filesystem, and the full missing path.
- Repair the official Codex installation rather than manually downloading a helper.
- Check newer linked issues because the restart workaround is not universal.
Scope
Environment and version notes
- The confirmed restart report used Windows 11, WSL2, Codex app 26.325, and CLI 0.118 alpha.
- A later issue reports similar symptoms not fixed by restart.
- Sources rechecked August 20, 2026.
Evidence
Sources
Source labels describe the evidence available on the checked date. A closed issue is not automatically a shipped fix.