Codex App (Windows/Store) self-terminates ~60s after launch on older GPUs: app CIG policy blocks bundled vk_swiftshader.dll; package left "Modified/NeedsRemediation"

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

26.721.3996.0 (also reproduced on 26.715.4045.0 and 26.715.10079.0)

What subscription do you have?

Pro

What platform is your computer?

Microsoft Windows NT 10.0.22000.0 x64 (Windows 11 Pro 21H2) - NVIDIA Quadro K2100M (driver 426.25) + Intel HD 4600 (driver 20.19.15.5126)

What issue are you seeing?

The app launches normally (full process tree, window appears), then the entire tree dies after ~60 seconds. After the first death the package is flagged "Modified, NeedsRemediation" and later launches fail at activation. Reinstalling from the Store gives exactly one more ~60-second run.

Root cause identified from Windows event logs: ChatGPT.exe enables the Code Integrity Guard (MicrosoftSignedOnly) mitigation for the process that loads the Vulkan fallback renderer. On machines where hardware GPU acceleration is unavailable, Chromium loads the app's own bundled app\vk_swiftshader.dll (not Microsoft-signed) and the kernel blocks it:

Microsoft-Windows-CodeIntegrity/Operational, Event 3033:
Code Integrity determ

### What steps can reproduce the bug?

1. Use a Windows 11 machine whose GPU/driver is on Chromium's blocklist (in my case: NVIDIA Quadro K2100M, driver 426.25 from 2019, and Intel HD 4600, driver 20.19.15.5126 from 2020), so Chromium falls back to SwiftShader software rendering.

2. Install the Codex App from the Microsoft Store and launch it.

3. The app starts normally (window appears, full process tree), then the entire process tree dies within ~60 seconds. At that moment the Windows event log "Microsoft-Windows-CodeIntegrity/Operational" records Event 3033: ChatGPT.exe attempted to load the app's own bundled app\vk_swiftshader.dll "that did not meet the Microsoft signing level requirements".

4. After this first death, run in PowerShell: (Get-AppxPackage OpenAI.Codex).Status - it now reports "Modified, NeedsRemediation" (even though all package files still hash-verify against AppxBlockMap.xml). All later launches fail at activation, with "Microsoft-Windows-AppModel-Runtime/Admin" logging Event 6, error 0x3CFC ("error encountered while checking the machine-level package status").

5. Reinstalling/restoring from the Store resets the flag and gives exactly one more ~60-second run, then steps 3-4 repeat. Reproduced on versions 26.715.4045.0, 26.715.10079.0 and 26.721.3996.0.

### What is the expected behavior?

_No response_

### Additional information

_No response_