Windows: granting write access to a directory on a non-system drive breaks exec in projectless tasks

What version of the Codex App are you using (From “About Codex” dialog)?

26.818.41509

What subscription do you have?

plus

What platform is your computer?

Microsoft Windows NT 10.0.26200.0 x64

What issue are you seeing?

Summary

On Windows, in a projectless Codex Desktop task, granting write access to a directory on a non-system drive can cause every subsequent exec command to fail before the process starts.

The failure happens even for Get-Date, before any filesystem write is attempted.

Actual result

The command fails before startup:

CreateProcess { message: "Rejected(\"Failed to create unified exec process: helper_unknown_error: setup refresh had errors\")" }

### What steps can reproduce the bug?

## Reproduction

1. Create a new task without selecting a project.
2. Confirm `Get-Date` succeeds.
3. Approve write access to an existing directory on a non-system drive, outside the task workspace (for example, `E:\some-directory`).
4. Do not perform any write.
5. Run `Get-Date`.

### What is the expected behavior?

exec success

### Additional information

_No response_

Start by reproducing the projectless Windows task: run Get-Date, grant write access to an existing directory on a non-system drive, and run Get-Date again. Trace the Windows exec setup refresh that reports “helper_unknown_error” and verify that exec still starts successfully after permission is granted without performing a write.