Windows: Desktop fails to start after auto-update - stale per-user backend (CODEX_CLI_PATH) and silently invalidated auth session

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

26.911.7940.0 (Windows package OpenAI.Codex_26.911.7940.0_x64__2p2nqsd0c76g0); bundled CLI in use: codex-cli 0.154.0-alpha.6.2

What subscription do you have?

ChatGPT Plus

What platform is your computer?

Windows 11 Pro, Build 26200, x64

What issue are you seeing?

After the Codex desktop app auto-updated, it failed to start: no window appeared for 4+ minutes while the main process burned CPU continuously.

Two independent root causes were found on this machine.

1. Stale bundled CLI in the per-user runtime directory

The app launches the executable selected by the user-level CODEX_CLI_PATH override, which points at the per-user runtime copy:
C:\Users<user>.codex.sandbox-bin\codex.exe

The MSIX package update only replaces the payload under C:\Program Files\WindowsApps\ and does NOT refresh this per-user copy. After the last update, all four backend binaries in .sandbox-bin differed from the ones bundled in the updated package - and comparing file sizes alone is not enough, because several differ in content while having identical sizes:

• codex.exe: size identical, content differs
• codex-code-mode-host.exe: differs (72,471,848 vs 72,471,856)
• codex-command-runner.exe: size identical, content differs
• codex-windows-sandbox-setup.exe: size identical, content differs

The app gave no indication it was running a stale app-server; startup simply hung.

2. Auth session silently invalidated, while login status still reports "logged in"

codex login status reported "Logged in using ChatGPT", while the stored tokens were unusable. Refreshing returned HTTP 401:
{"error":{"message":"Your session has ended. Please log in again.","code":"refresh_token_invalidated"}}

The id_token was expired and the refresh_token had been revoked server-side (the machine had been idle for several days). Nothing in the UI surfaced this - the app just failed to start.

What steps can reproduce the bug?

1. Use Codex Desktop on Windows with a user-level CODEX_CLI_PATH set. This override is the documented workaround for the "Unable to locate the Codex CLI binary" startup failure (see #40700 / #40752 / #40796).
2. Let the app auto-update through the MSIX store while the override is in place.
3. Fully exit and relaunch the app.
4. Observe: no window appears and the main process consumes CPU indefinitely.
5. Compare each .exe under %USERPROFILE%.codex.sandbox-bin against the same-named file under the updated package's app\resources directory - hashes differ even when file sizes match.
6. Separately, leave the app unused for several days and relaunch: codex login status still says logged in, but POST https://auth.openai.com/oauth/token with grant_type=refresh_token returns 401 refresh_token_invalidated.

What is the expected behavior?

1. When the desktop app updates, it should validate the version and/or protocol capabilities of the app-server binary it is about to launch (including one selected via CODEX_CLI_PATH), and either refresh it automatically or refuse to start with an actionable error naming the configured path and the detected version mismatch - instead of hanging silently.

2. Before opening a thread, the app should verify that stored credentials are still usable (e.g. probe the refresh endpoint). If the session has been invalidated server-side, it should prompt the user to sign in again, instead of continuing to report codex login status: Logged in using ChatGPT.

Additional information

No response

Start by tracing desktop startup with a user-level CODEX_CLI_PATH, comparing binaries in %USERPROFILE%.codex.sandbox-bin with the package's app\resources directory. Then inspect the codex login status flow and the OAuth refresh endpoint behavior for refresh_token_invalidated. Done means stale binaries are detected with an actionable error or refreshed, and invalid sessions prompt the user to sign in again instead of reporting a usable login.