[Windows app] Normal shell launch exits; direct COM activation works without disabling GPU

App version

ChatGPT / Codex Windows desktop app 26.908.4834.0, distributed as OpenAI.Codex.

Problem

The app can exit silently shortly after normal Windows shell activation. Direct activation using the standard IApplicationActivationManager API with no command-line arguments opens the visible app successfully, with GPU acceleration enabled.

Changing both the activation method and adding --disable-gpu can misleadingly suggest a GPU problem. Comparing the same direct activation method with an empty argument string shows that disabling GPU is not necessary in this case.

Reproduction on an affected Windows session

1. Fully exit the app.

2. Launch using the normal app entry, or:

   Start-Process explorer.exe -ArgumentList 'shell:AppsFolder\OpenAI.Codex_2p2nqsd0c76g0!App'
   

3. The app starts and exits before a usable window appears.

4. In a non-elevated process, call the documented Windows COM activation API with:

   IApplicationActivationManager.ActivateApplication(
       "OpenAI.Codex_2p2nqsd0c76g0!App", "", AO_NONE, out pid)
   

5. The app opens successfully without GPU-disabling or sandbox-disabling flags. This comparison was repeated with fresh app processes.

The original trigger for the affected shell state is not yet isolated. Restarting Explorer helped one normal launch but did not permanently resolve the recurrence.

Expected behavior

Normal shell activation should work as reliably as direct COM activation. If child-process initialization fails, the app should provide an actionable error rather than silently exiting.

Related reports checked

#37602 describes clean exit depending on the presence of arguments; this case differs because direct COM activation works with an empty argument string. #25221 describes shell activation opening Chrome, which is not the observed behavior here. GPU-related startup reports may have a similar symptom, but the activation route should be controlled during diagnosis.

This minimal report deliberately contains no machine-specific configuration, account data, raw logs, memory dumps, or local project information.

Reproduce the two entry points described: shell:AppsFolder\OpenAI.Codex_2p2nqsd0c76g0!App and IApplicationActivationManager.ActivateApplication with an empty argument string. Compare startup and child-process initialization while keeping GPU settings unchanged; done means normal shell activation remains open reliably or reports an actionable initialization error.