Windows Codex App: unified exec fails with `helper_unknown_error: setup refresh had errors`

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

26.819.11345

What subscription do you have?

ChatGPT Plus

What platform is your computer?

Microsoft Windows NT 10.0.22631.0 x64

What issue are you seeing?

The Codex App cannot start the unified exec terminal helper.

Exact error:

Failed to create unified exec process: helper_unknown_error: setup refresh had errors

The failure occurs before any command starts, including read-only commands such as:

git rev-parse HEAD

Reproduced in:

• the existing project chat;
• a newly created chat in the same local project;
• after restarting the Codex App;
• after restarting Windows;
• after Workspace dependency diagnostics reported Codex dependencies look healthy;
• after reinstalling the Workspace bundle;
• with [windows] sandbox = "elevated";
• with [windows] sandbox = "unelevated".

The local project path contains Cyrillic characters. The project and commands worked previously with the same path.

Expected behavior:
The unified exec helper starts and executes the read-only command.

Actual behavior:
The helper fails during setup refresh before the command is launched.

Impact:
Terminal preflight cannot run. Repository staging and commit operations are intentionally paused. No repository changes, staging, or commits were performed during troubleshooting.

The existing .codex/.sandbox/sandbox.log does not contain the current failures. Its last records predate the currently installed Codex App version.

Feedback ID:
01a03853-2618-7b90-9ce3-1d74d3c81a1d

What steps can reproduce the bug?

1. Open the Codex App on Windows.
2. Open an existing local-project chat or create a new chat in the same project.
3. Ask Codex to run a basic read-only terminal command such as git rev-parse HEAD.
4. The terminal helper fails before the command starts with: Failed to create unified exec process: helper_unknown_error: setup refresh had errors.
5. Repeat after restarting the app or creating another project chat; the same failure occurs.

What is the expected behavior?

The unified exec terminal helper should initialize successfully and execute the requested command in the configured local project directory.

Additional information

No response

Start by reproducing the failure in the Windows Codex App with git rev-parse HEAD, using the reported project path and both sandbox settings. The report names no source file or test; the .codex/.sandbox/sandbox.log predates the failure, so use the reproducible error and Feedback ID as the initial investigation anchors. Done means the unified exec helper starts and runs the read-only command.