Remote/mobile thread routing breaks with two macOS users on one Mac using Fast User Switching
What version of the Codex App are you using?
ChatGPT desktop app 26.707.71524 (bundle 5263), using the Codex surface.
What platform is your computer?
macOS 15.7.7 (24G720), one Mac with two macOS login users and Fast User Switching enabled.
The remote client is the ChatGPT mobile app on iPhone.
What issue are you seeing?
Codex Remote/mobile does not handle two simultaneously used macOS login users on the same Mac cleanly.
Each macOS user runs Codex. With Fast User Switching, both desktop user sessions can remain logged in and active. On the iPhone, only the threads associated with one macOS user are visible (currently the second user); threads from the other macOS user are missing.
The mobile app also produces repeated errors or confusing states when it tries to operate across this setup, including failures to:
- search threads;
- send messages to other threads;
- consistently identify which desktop user/session owns a thread.
The result feels like the two macOS user sessions are being collapsed into one remote host/session identity, or one session is replacing the other. That is an inference from the behavior, not a confirmed cause.
This is both a bug report and a feature request: Codex should explicitly support multiple macOS login users on one physical Mac, or clearly represent and isolate each OS-user session in Remote/mobile.
What steps can reproduce the bug?
- On one Mac, create/use two separate macOS login users.
- Run and sign into Codex under macOS user 1.
- Use Fast User Switching to switch to macOS user 2 without logging out user 1.
- Run and sign into Codex under macOS user 2.
- Open Codex/Remote in the ChatGPT app on iPhone.
- Inspect the available thread list.
- Try to search threads and send a message to a thread associated with the other macOS user.
Observed:
- only user 2's threads are visible on the phone;
- user 1's threads are absent;
- thread search and cross-thread messaging frequently error or behave inconsistently.
What is the expected behavior?
Each macOS login user's Codex session should be treated as a distinct remote host/session namespace, even when both sessions run on the same physical Mac.
On mobile, the user should be able to:
- see both macOS user sessions as separate, clearly labeled sources;
- browse and search the correct thread set for each session;
- send a message to any visible thread without ownership/routing errors;
- switch between the two sessions without one replacing or corrupting the other's remote state.
If simultaneous Fast User Switching sessions are not supported, the app should detect this case and show one clear, actionable explanation instead of partial thread visibility and repeated search/message errors.
Additional information
Related reports exist for Remote Control hydration and state propagation, but this report is specifically about host/session identity and thread routing when two macOS login users run Codex concurrently on one Mac.
No account identifiers, OS usernames, private thread content, or logs are included in this public report.