A Hidden Character Can Hide Your Codex Sessions
Today I learned that a single weird Unicode line separator (U+2028) can make Codex.app skip loading session history. I quit and restarted the app and all my
sessions vanished, which was alarming.
The fix was simple: remove the offending U+2028 characters from the sessions JSONL file. After that, I quit and restarted again and everything came back.
Clearly that one character was
What to ask Codex
- Search the Codex sessions folder1 for
U+2028. - Show the exact lines where it appears.
- Remove those characters from the affected session file(s).
- Verify the characters are gone.
- Quit and restart Codex.app to confirm sessions load again.
FWIW You'll probably never hit this issue
this is in the next release, you just helped speed up the testing 🙏
— Andrew Ambrosino (@ajambrosino) February 4, 2026
1. You’ll want to search the Codex sessions folder in your home directory. On macOS, the path is ~/.codex/sessions. Ask Codex to scan that folder for hidden Unicode line separators and clean them up.