[Windows 26.707.8479.0] Opening a blank in-app Browser tab immediately terminates Codex Desktop

What version of the Codex App are you using?

Codex Desktop (Microsoft Store/MSIX) 26.707.8479.0 x64.

What platform is your computer?

Windows x64, OS build 10.0.26200.

What issue are you seeing?

After the recent Codex Desktop update, starting the in-app Browser can terminate the entire Codex application.

The failure does not require loading a website. Creating a new in-app Browser tab at about:blank is enough: the Browser loading UI appears briefly, then the complete Codex window exits. Codex subsequently relaunches.

Reproduction rate in this session: 2/2.

What steps can reproduce the bug?

1. Start Codex Desktop on Windows.
2. Start the in-app Browser / Browser Use integration.
3. Create a new Browser tab.
4. Observe the Browser loading UI briefly.
5. The entire Codex Desktop application exits and later relaunches.

One reproduction also occurred while creating an in-app Browser tab for a localhost preview, but the second controlled reproduction required only a new blank tab.

What is the expected behavior?

The in-app Browser should open a blank tab and keep the main Codex Desktop application running.

If Browser initialization fails, it should show a recoverable error without terminating the desktop host or interrupting the active task.

Actual behavior

The Browser briefly starts loading, then the whole Codex Desktop AppX container is destroyed. The app relaunches several seconds later.

Diagnostic evidence

Windows AppModel-Runtime/Admin recorded the following for the controlled reproduction (local time, Europe/Berlin):

• 2026-07-14 00:13:54 — Event ID 217: destroyed Desktop AppX container for package OpenAI.Codex_26.707.8479.0_x64__2p2nqsd0c76g0.
• 2026-07-14 00:13:59 — Event IDs 210/211/201: created a new AppX container and launched a new Codex process.

An earlier reproduction recorded another Event ID 217 at 2026-07-13 23:56:24.

No matching Windows Application Error event was found in the inspected period.

A feedback report was uploaded from the restarted app:

Feedback ID: 019f5d77-ac40-73d1-a522-0413b937d35d

Related issues

• #32683 — similar native crash when Browser Use opens a page; this report narrows the trigger to creation of an about:blank tab on build 26.707.8479.0.
• #32040 — opening the in-app Browser can hang/close Codex.
• #32798 — external site reaches DOM-ready and Codex exits on the same app build.

The key distinguishing detail here is that no navigation or page DOM-ready event is required; opening the blank Browser tab alone is sufficient.