[Windows] New local chat in an existing ChatGPT Project reports "Unknown local project"

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

26.908.8172.0

What subscription do you have?

ChatGPT Plus

What platform is your computer?

Microsoft Windows NT 10.0.26200.0 x64

What issue are you seeing?

A ChatGPT Project that already contains working local Codex chats cannot be used reliably when creating another local chat.

When I start a new Codex chat in Local mode from the existing project, the app displays this warning (Russian UI):

Не удалось использовать этот проект для локального чата
Failed to use this project for a local chat

Existing local Codex chats associated with the same project continue to open and run normally on my computer. Regular ChatGPT chats in the project also work. The problem occurs specifically during creation of a new local Codex chat.

Relevant Codex Desktop log messages:

Failed to prewarm local conversation errorMessage="Unknown local project"
ChatGPT project context sync failed projectSaveCount=0 stage=filesystem status=null

What steps can reproduce the bug?

1. Open the ChatGPT desktop app on Windows.
2. Open the existing ChatGPT Project “ЕК-Регион”.
3. Start a new Codex chat and select Local execution.
4. Enter any prompt and attempt to create/start the chat.
5. The warning “Не удалось использовать этот проект для локального чата” appears.

Existing local Codex chats inside the same project remain functional.

Feedback ID: 01a0a8b6-9c43-7403-9213-f4d9319d7ffa

What is the expected behavior?

A new local Codex chat should be created inside the selected ChatGPT Project and receive the project instructions and sources, just like the existing local Codex chats already associated with that project.

Additional information

The project contains both regular ChatGPT chats and working local Codex chats. Existing local chats show that they run on this computer and continue to work correctly.

The failure is limited to the new-chat creation flow. Logs show that local conversation prewarming cannot resolve the project and that ChatGPT project context synchronization fails at the filesystem stage. This suggests a project registry/cache or project-context sync issue during creation, rather than a general limitation on local chats in ChatGPT Projects.

GitHub suggested #45724 as a potential duplicate, but that report requires WSL mode to be enabled. WSL is not installed on this computer; Codex logs show that wsl.exe --status returns that Windows Subsystem for Linux is not installed. Therefore this appears to be a different failure path.

I can provide screenshots showing the existing working local chats and the warning if needed.

Start by reproducing the Windows flow in the Codex desktop app using the existing project “ЕК-Регион,” then inspect the Codex Desktop logs around “Unknown local project” and “project context sync failed.” Done means a new Local chat is created in the selected project with its instructions and sources, while existing local chats continue to work.