macOS App: 100% CPU on Launch and ~60s UI Freeze on Any Interaction (M1 Pro, 32GB, Tahoe 26.1) #11596

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

260210.1703

What subscription do you have?

Plus

What issue are you seeing?

After launching the Codex macOS app, CPU usage immediately jumps to ~100% and remains there continuously.

The UI is initially responsive, but any interaction (typing, sending a prompt, navigating the interface) causes the app to freeze. The freeze lasts approximately 60 seconds before the UI updates again. Responses eventually arrive, but the interface remains significantly laggy.

The behavior is consistent and reproducible on every launch.

The application does not crash immediately, but becomes practically unusable due to extreme latency after each interaction. CPU remains abnormally high during usage.

This issue was not observed prior to recent updates (exact regression version unknown on this machine).

What steps can reproduce the bug?

1. Start the macOS Codex app.
2. Observe CPU usage in Activity Monitor (~100% immediately).
3. Type and submit a prompt (or perform any interaction).
4. App freezes for approximately 60 seconds before responding.

5. Repeat — behavior is consistent.

What is the expected behavior?

1. CPU usage should remain within normal idle bounds after launch.
2. Submitting prompts should not freeze the UI.
3. The app should remain responsive during processing.

Additional information

1. The issue persists after restarting the app.
2. No visible error messages are shown.
3. The app does not fully crash but becomes extremely slow.
4. Occurs under normal system load conditions.