Windows Codex 26.901.6511.0 intermittently opens to a blank white screen

Summary

On Windows, Codex frequently launches to a completely blank white window. Repeatedly closing and relaunching the app eventually allowed the UI to appear, but the problem is intermittent and remains unresolved.

Environment

• Windows desktop app
• Codex version: 26.901.6511.0 (x64)
• Microsoft Store stable channel
• Time zone: UTC+8

What happened

Between 2026-09-08 10:37 and 10:43 UTC+8, I performed five separate launches after moving the app's GPU, shader, HTTP, and code cache directories to timestamped backups. The app still repeatedly opened to a blank white window. It finally displayed the UI on a later launch at about 10:44, without a reliable change that explains the recovery.

The app logs for blank-screen launches still report:

• window main frame finished load
• window ready-to-show
• React root render requested

The successful launch also contains Failed to load shell env ... Timed out after 5000ms, so that warning does not distinguish the failed launches. No render-process-gone event or Crashpad dump was found in the inspected logs.

Steps to reproduce

1. Fully exit Codex.
2. Launch Codex from the registered Microsoft Store app entry.
3. The main window sometimes remains entirely white.
4. Close and relaunch repeatedly; the UI may eventually appear.

Expected behavior

The main UI should render reliably on every launch.

Additional context

Clearing the caches listed above did not produce a stable fix. The logs reaching the React render request while the window remains white may point to a renderer, GPU composition, or first-frame presentation issue.

Uploaded thread: 019c0d37-d2b6-74c0-918f-0e64af9b6e14

No source files or tests are named; start by reviewing the uploaded thread and comparing the blank-screen and successful-launch logs around the React render request, ready-to-show event, and shell-environment timeout. Done means identifying a reproducible cause and establishing a reliable fix for the intermittent white window.