Codex App crashes/hangs when opening local HTML with the built-in browser on Windows

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

From Windows Error Reporting: Codex.exe 149.0.7827.115 Installed package observed previously: OpenAI.Codex_26.616.10790.0_x64 [Please verify with “About Codex” dialog]

What subscription do you have?

CHATGPT Pro

What platform is your computer?

Microsoft Windows NT 10.0.22000.0 x64

What issue are you seeing?

The Codex desktop app repeatedly hangs or exits when I try to use the built-in browser to open a local HTML page.

There is no recoverable error shown inside the Codex UI. The app becomes unresponsive or disappears, and I need to restart Codex. Windows Event Viewer records this as an AppHangTransient for Codex.exe.

Recent Windows Error Reporting entries:

• 2026-06-27 11:55:14
• Event name: AppHangTransient
• P1: Codex.exe
• P2: 149.0.7827.115
• Report ID: 9d4fab86-da3e-4df4-8f0c-cdc94dd74008

• 2026-06-25 16:17:52
• Event name: AppHangTransient
• P1: Codex.exe
• P2: 149.0.7827.115
• Report ID: 12253866-b740-4d18-aee2-6a1542c340bb

• 2026-06-23 22:15:19
• Event name: AppHangTransient
• P1: Codex.exe
• P2: 149.0.7827.115
• Report ID: 07027882-61de-4302-bbfe-37b00f18a518

What steps can reproduce the bug?

1. Launch the Codex desktop app on Windows.
2. Open a local workspace/thread.
3. Try to use the built-in Codex browser / in-app browser to open or preview a local HTML file generated in the workspace.
4. The Codex app hangs or exits/crashes shortly after the browser is invoked.
5. Restarting Codex does not resolve the issue.

Troubleshooting already tried:

• Fully exited and restarted Codex.
• Moved aside the bundled browser plugin cache:

~/.codex/plugins/cache/openai-bundled/browser

• Codex regenerated the browser cache, but the issue still reproduces.
• Reduced local git status overhead in the workspace by excluding large generated/untracked directories and setting status.showUntrackedFiles=no; this improved general git status performance but did not fix the browser crash/hang.

What is the expected behavior?

The built-in browser should either open the HTML page successfully, or fail gracefully with an error message if the URL or local file access is not allowed.

The Codex desktop app should not hang, disappear, or require a restart.

Additional information

This appears related to invoking the built-in browser rather than the HTML content itself. A minimal static HTML file with no scripts/external resources was enough to trigger browser-related failure behavior.

When attempting direct file:// access, Browser Use reports that the URL is blocked by policy, which is understandable. However, the desktop app should remain stable and report the policy error instead of hanging/crashing.

The issue has reproduced multiple times across several days, and Windows Event Viewer consistently reports AppHangTransient for Codex.exe.