Windows app Settings crashes when external agent import panel renders (`path.win32` is null)

What version of the Codex App are you using?

Codex Windows Store app 26.429.20946 / package appears as OpenAI.Codex_26.429.2026.0_x64__2p2nqsd0c76g0.

What subscription do you have?

Unknown / not relevant.

What platform is your computer?

Windows 10.0.26200, x64.

What issue are you seeing?

Opening Codex Settings shows the generic error page:

Oops, an error has occurred

Clicking Try again repeats the same error. Checking for updates and restarting the app did not fix it.

The app Sentry scope/log shows this exception:

TypeError: Cannot read properties of null (reading 'dirname')
    at $e (app://-/assets/gpu-tearing-debug-settings-CC_rYath.js:2:1487)
    at Qe (app://-/assets/gpu-tearing-debug-settings-CC_rYath.js:2:1044)
    at app://-/assets/gpu-tearing-debug-settings-CC_rYath.js:2:146
    at Array.flatMap (<anonymous>)
    at qe (app://-/assets/gpu-tearing-debug-settings-CC_rYath.js:2:87)
    at Je (app://-/assets/gpu-tearing-debug-settings-CC_rYath.js:2:356)
    at ut (app://-/assets/gpu-tearing-debug-settings-CC_rYath.js:2:14389)
    at ot (app://-/assets/gpu-tearing-debug-settings-CC_rYath.js:2:2476)
    at vo (app://-/assets/use-model-settings-xR9aSjKo.js:9:47561)

Despite the chunk filename, this appears to be in the external-agent config import / migrate-to-Codex Settings code, not GPU settings.

Investigation / likely cause

Inspecting the packaged webview bundle shows the crashing function:

function $e(e,t){
  return e.cwd!=null&&e.cwd!==``
    ? e.cwd
    : t==null||t===``
      ? null
      : (t.includes(`\\`) ? Z.default.win32 : Z.default.posix).dirname(t)
}

On this Windows install, the browserified path object appears to have win32 as null, so when codexHome contains backslashes, Settings attempts:

Z.default.win32.dirname(t)

and crashes because win32 is null.

The same module also contains:

var ke = `external-agent-config-import-settings`

and the path is called while rendering migration items:

Je({ migrationItems: S.detectedItems, codexHome: e, isEnabled: m })

This seems to happen merely because Codex detects external-agent config sources on disk. No migration/import was requested or performed.

Steps to reproduce

1. On Windows, have Codex app 26.429.20946 installed.
2. Have external-agent config detectable by Codex, e.g. Claude/Cursor config under the user profile.
3. Open Codex Settings.
4. Settings crashes to the generic error page.

Expected behavior

Settings should open normally. If external-agent config import is available, it should render safely on Windows, or skip malformed/unavailable path conversion without crashing the entire Settings page.

Workarounds tried

• Check for updates
• Restart Codex
• Remove a suspicious selected-remote-host-id from Codex global state after backing it up
• Move Codex Chromium Local Storage / Session Storage / Cache aside so webview state regenerates

None fixed the Settings crash.

No Claude files were modified and no migration was performed.