Codex Desktop blank window with renderer pegged at 100% CPU on startup

Summary

Codex Desktop opens to a blank window and a renderer process spins at roughly
100% CPU during startup. The issue reproduces with both the normal Chromium
profile and a temporary clean Chromium profile, so ordinary browser cache,
cookies, and local storage are unlikely to be the primary trigger.

Environment

• Product: Codex Desktop
• App version: 26.602.71036
• Bundle ID: com.openai.codex
• Chromium: 149.0.7827.54
• macOS: 26.3.1
• Architecture: arm64

Reproduction

Normal launch:

open -a Codex

Clean-profile launch:

open -n -a Codex --args --user-data-dir=/private/tmp/codex-clean-profile-20260609T0532

Both launch modes produced a blank desktop app window and a hot renderer process.

Observed behavior

Normal profile launch:

• Main app: /Applications/Codex.app/Contents/MacOS/Codex
• Hot child process: Codex (Renderer)
• CPU: 100.0%

Temporary clean profile launch:

• Main app: /Applications/Codex.app/Contents/MacOS/Codex --user-data-dir=/private/tmp/codex-clean-profile-20260609T0532
• Hot child process: Codex (Renderer)
• CPU: approximately 98.7%

No new Crashpad dump was written during the hang. Older pending renderer dumps
were present, but not from this reproduction.

Process sample

A 5-second sample of the hot renderer showed the process spending all samples
in V8 / JavaScript execution paths, especially microtask / script compilation /
app-code paths. It did not point to Git, Python, repository validation, GPU, or
filesystem cleanup as the immediate source of the spin.

Representative anchors from the sample:

Process: Codex (Renderer)
Version: 149.0.7827.54
ChromeMain
v8::MicrotasksScope
v8::Function::Call
v8::ScriptCompiler::CompileModule

Additional checks

• Reproduced with --user-data-dir pointing at a brand-new temporary directory.
• macOS unified logs around the incident showed app/window/XPC noise and
  voluntary app exit after manual termination, but no clear app exception.
• Local Codex SQLite state databases passed pragma integrity_check.
• The active repository checkout stayed clean and was not implicated.

Expected behavior

Codex Desktop should hydrate the UI after launch and should not peg a renderer
process at 100% CPU.

Actual behavior

The native shell opens, but the window remains blank and a renderer process spins
until the app is terminated.

Attachments available

I have a local incident bundle with:

• screenshot of the blank app shell
• 5-second sample output from the hot renderer
• SHA-256 checksums for both files

I am not attaching the screenshot publicly because it includes personal desktop
context. I can provide the process sample and/or sanitized screenshot if useful.