macOS 27: Native transport disconnected leaves persistent uncloseable ChatGPT window off-screen

What version of the ChatGPT/Codex App are you using?

26.908.31748

What subscription do you have?

Unknown / not relevant to reproduction

What platform is your computer?

Darwin 27.0.0 arm64 arm (macOS 27.0, build 26A428)

What issue are you seeing?

The Edge/Chrome ChatGPT side panel cannot connect to the running ChatGPT desktop app and shows:

• Open or update the ChatGPT desktop app
• The Edge side panel could not connect to the ChatGPT desktop app
• Technical details: Native transport disconnected

At the same time, a separate ChatGPT-owned error window remains pinned on the far right side of the macOS desktop. It says that ChatGPT encountered a problem and asks the user to retry. The window cannot be closed or interacted with normally, and it reappears/persists after restarting.

Local window inspection shows the abnormal ChatGPT-owned window at layer 3 with bounds approximately X=1404, Y=-802, Width=772, Height=2069, so much of it is off-screen.

Steps to reproduce

1. Run ChatGPT desktop app 26.908.31748 on macOS 27.0.
2. Open the ChatGPT side panel in Edge or Chrome.
3. The side panel reports Native transport disconnected even though the desktop app is running.
4. A ChatGPT error window remains stuck at the right edge of the desktop and cannot be dismissed normally.

Troubleshooting already attempted

• Clicked Retry / Try again / Update.
• Restarted ChatGPT and the browsers.
• Removed the ChatGPT browser extension from both Edge and Chrome.
• The right-side error window and connection failure still persist.

Expected behavior

The browser side panel should connect to the running desktop app. If the native transport fails, the error window should remain on-screen, respond to its controls, and be dismissible.

Related issues

• #42618 — exact Native transport disconnected error.
• #38530 — macOS 27 native-host detection/TCC failure.
• #42684 — macOS 27 native-host/Gatekeeper failure.
• #32792 — popped-out ChatGPT window controls do not respond.

This appears to combine the native-host connection failure with a detached-window positioning/control bug. The exact combination persists on a newer desktop build than the related reports.

The issue names no repository files or tests, so begin by reproducing the macOS 27 behavior with ChatGPT 26.908.31748 and reviewing related issues #42618, #38530, and #42684. Done means the browser side panel connects to the running desktop app, or a native-transport failure leaves an on-screen, interactive, dismissible error window.