Windows Codex: new active threads disappear in a project with ~120+ threads; archiving old threads fixes it

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

Unknown at the time of filing because I am currently away from the PC. I will update the issue with the exact version from the “About Codex” dialog.

What subscription do you have?

ChatGPT Plus

What platform is your computer?

Windows x64. Exact Windows version and build are currently unavailable because I am filing this report from mobile. I will update the issue with the PowerShell output.

What issue are you seeing?

In a large Codex project containing approximately 120 or more threads, newly created active Codex threads repeatedly disappeared from the project thread list.

The affected threads disappeared both from the Windows Codex app and from ChatGPT iOS Remote. In some cases, an active run stopped without producing the expected final response. When I attempted to continue the work, the thread disappeared again.

The underlying repository changes were not deleted. The uncommitted work remained in the local Git working tree and could be completed from a newly created thread. This indicates that the failure affects thread visibility, indexing, or session continuity rather than the repository files themselves.

The issue happened several times across different tasks.

After I archived a large number of older completed threads in the same project, newly created threads stopped disappearing. No other configuration change was made at that time.

A concrete example:

• A Codex Efficiency Foundation task was nearly complete when its thread disappeared.
• A replacement continuation thread found the existing work in the Git working tree.
• It completed the remaining work in 49 seconds without repeating installation, benchmarks, or previous checks.
• It created commit:

e54a2e7 chore(codex): add token-efficient workflow

This appears to be related to project thread count, sidebar pagination, local thread indexing, or synchronization between the Windows Codex app and mobile Remote.

<img width="660" height="1434" alt="Image" src="https://github.com/user-attachments/assets/5c484194-7d74-447c-bf23-11c5e5de8811" />
<img width="660" height="1434" alt="Image" src="https://github.com/user-attachments/assets/0c7fc622-6523-4bfa-8f8c-28e68b61b0a3" />
<img width="660" height="1434" alt="Image" src="https://github.com/user-attachments/assets/b790f899-128f-4ab4-b529-4d4c7934d825" />
<img width="660" height="1434" alt="Image" src="https://github.com/user-attachments/assets/376dcf22-c9e9-482d-86de-ac121b040891" />
<img width="660" height="1434" alt="Image" src="https://github.com/user-attachments/assets/476686f2-a1db-471b-a576-4aaccb5a455b" />

What steps can reproduce the bug?

1. Open a Codex project in the Windows app that contains a large number of existing threads. In my case, the project contained approximately 120 or more threads.

1. Create a new Codex thread in that project.

1. Send a substantial implementation task and allow it to run for several minutes.

1. Optionally observe the same task through ChatGPT iOS Remote.

1. During or near the end of the run, the task may stop without producing the expected final response.

1. Return to the project thread list.

1. The newly created active thread may no longer appear in the project list.

1. Check both the Windows Codex app and iOS Remote. In my case, the thread was missing from both.

1. Create another thread and continue from the existing Git working tree.

1. The replacement thread can find the uncommitted changes left by the disappeared thread.

1. The disappearance may occur again with another newly created thread.

1. Archive a large number of older completed threads in the affected project.

1. Create another new thread.

1. After archiving the older threads, newly created threads remain visible and the issue stops reproducing.

The problem occurred multiple times before archiving and stopped immediately afterward.

A session ID is currently unavailable because the affected threads disappeared from the interface. I can provide additional diagnostics when I return to the Windows PC.

What is the expected behavior?

Newly created and active Codex threads should remain visible and accessible regardless of how many older threads exist in the project.

A large project should use reliable pagination or virtualization without hiding or evicting active threads.

Windows Codex and mobile Remote should display a consistent thread inventory.

An active run should either complete normally or return an explicit error. It should not silently stop while the associated thread disappears from the project list.

Archiving unrelated older threads should not be required to make new Codex threads reliable.

Additional information

Impact:

• Active development sessions became inaccessible.
• Runs stopped before returning their final reports.
• Replacement threads had to recover work from the Git working tree.
• Paid Codex usage was consumed by interrupted and repeated sessions.
• Mobile Remote could not be relied on for monitoring long-running tasks.

No repository data was lost in the observed cases. The local Git working tree retained the implementation.

The strongest evidence is commit:

e54a2e7 chore(codex): add token-efficient workflow

The replacement thread created this commit in 49 seconds and explicitly reported that installation, benchmarks, and earlier checks were not repeated. This confirms that the disappeared thread had already completed most of the work.

The behavior changed immediately after I archived many older completed threads in the project. New threads then stopped disappearing.

Possible areas to investigate:

• project-level thread pagination;
• sidebar virtualization;
• local thread index or cache;
• app-server thread listing with large projects;
• active-thread eviction;
• synchronization between Windows Codex and mobile Remote;
• cache invalidation triggered by archiving.

Observed on July 14, 2026, approximately 06:56–07:22, UTC+3.

I can later provide the exact Windows build, Codex App version, diagnostic output, and additional information from the PC.