macOS App: 100% CPU on Launch and ~60s UI Freeze on Any Interaction (M1 Pro, 32GB, Tahoe 26.1)
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?
- Start the macOS Codex app.
- Observe CPU usage in Activity Monitor (~100% immediately).
- Type and submit a prompt (or perform any interaction).
- App freezes for approximately 60 seconds before responding.
<img width="955" height="643" alt="Image" src="https://github.com/user-attachments/assets/fd7da2a8-2ea6-47d1-a7a6-9468ff40cf8d" />
- Repeat — behavior is consistent.
What is the expected behavior?
- CPU usage should remain within normal idle bounds after launch.
- Submitting prompts should not freeze the UI.
- The app should remain responsive during processing.
Additional information
- The issue persists after restarting the app.
- No visible error messages are shown.
- The app does not fully crash but becomes extremely slow.
- Occurs under normal system load conditions.
6 Comments
Potential duplicates detected. Please review them and close your issue if it is a duplicate.
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Thanks for reporting the issue. I wonder if this is the same issue as #11524.
Sounds identical to my issue reported here - #11584
For me downgrading to 260205.1301 (554) fixes the issue. Extremely high CPU use was initially introduced in version 260206.1448 (where CPU usage was at 100% continuously).
However, update 26.212.1823 seems to have fixed the issue, for me at least.
@marrakunta, please try the latest version and see if that addresses your original issue.
I am on Version 26.212.1823 (661) and see similar behaviour. CPU is almost constantly over 100% (161% as I write this); UI is unbearably sluggish.
Same specs as OP (m1 mac, 32gb); but earlier macos version (15.7.3 (24G419)).
Same Mac M1 Pro - 14 inch - 32GB (26.212.1823 (661))