Slow thread switching / loading on Codex macOS desktop app (v26.429.30905, regression) #20802

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

Version 26.429.30905 (2345)

What subscription do you have?

Pro

What platform is your computer?

Darwin 24.5.0 arm64 arm (M4 Pro 24GB RAM)

What issue are you seeing?

After updating to Codex macOS desktop app version 26.429.30905 (2345), switching between threads is noticeably slower. Previously, thread switching was near-instant, but now it consistently takes a few seconds (2-4s) to load each thread.

What steps can reproduce the bug?

1. Update Codex macOS desktop application to version 26.429.30905 (2345)
2. Open Codex
3. Switch between existing threads
4. Observe delay when loading content

What is the expected behavior?

Thread switching should be near-instant and responsive.

Additional information

• Regression from previous versions
• Occurs consistently when switching threads
• Most noticeable when first opening the app
• Initial thread load has the biggest delay
• Performance improves after a thread has been opened once (likely cached), but remains noticeably slower than previous versions