codex - 💡(How to fix) Fix Windows Codex Desktop Browser Use fails to start app-server despite working npm CLI [4 comments, 4 participants]

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

26.422.8496.0

What subscription do you have?

ChatGPT Plus

What platform is your computer?

Windows 10 Home, 64-bit, build 26100

What issue are you seeing?

Codex Desktop Browser Use does not work on Windows.

When I use the Browser Use plugin, it only sees an about:blank tab and cannot navigate or inspect the in-app browser. Attempting to navigate with Browser Use fails with:

failed to start codex app-server: The system cannot find the path specified. (os error 3)

Inside Codex, Browser Use returns:

agent.browser.tabs.list() => about:blank agent.browser.user.openTabs() => []

A simple test like navigating to https://example.com fails with the same app-server error.

I also tested the packaged Codex executable directly in PowerShell:

& "C:\Program Files\WindowsApps\OpenAI.Codex_26.422.8496.0_x64__2p2nqsd0c76g0\app\resources\codex.exe" --help

That fails with:

Access is denied

I installed the standalone npm CLI:

npm.cmd install -g @openai/codex

Then:

codex.cmd app-server --help

works correctly and prints the app-server help text.

So the standalone CLI appears healthy, but Codex Desktop Browser Use still fails, likely because it is trying to start the packaged WindowsApps codex.exe or otherwise not resolving the working codex.cmd from PATH.

I already tried:

• Restarting Windows
• Terminating Codex
• Repairing Codex from Windows Apps settings
• Resetting Codex
• Uninstalling/reinstalling Codex Desktop
• Fully quitting/reopening Codex Desktop
• Installing the npm CLI

The issue still persists.

What steps can reproduce the bug?

1. Install and open Codex Desktop on Windows.
2. Open a Codex thread with the Browser Use plugin enabled.
3. Ask Codex to use Browser Use or run a basic Browser Use navigation test.
4. Browser Use initializes but only sees an about:blank tab.
5. Attempt to navigate the Browser Use tab to a simple site such as https://example.com.
6. The navigation fails with:

failed to start codex app-server: The system cannot find the path specified. (os error 3)

Additional reproduction/check:

1. In PowerShell, run the packaged Codex executable directly:

& "C:\Program Files\WindowsApps\OpenAI.Codex_26.422.8496.0_x64__2p2nqsd0c76g0\app\resources\codex.exe" --help

1. It fails with:

Access is denied

1. Install standalone CLI:

npm.cmd install -g @openai/codex

1. Run:

codex.cmd app-server --help

1. This works, but Browser Use in Codex Desktop still fails with the same app-server error.

What is the expected behavior?

Browser Use should start or connect to a working Codex app-server, attach to the in-app browser tab, and allow normal browser automation actions such as navigation, screenshots, DOM snapshots, clicks, and form interactions.

For example, navigating to https://example.com through Browser Use should load the page and allow DOM/screenshot inspection instead of failing with an app-server path error.

Additional information

Additional context: I am logged into GitHub with a different account than my ChatGPT/Codex account. I do not know if this is related, but I wanted to mention it. The Browser Use failure appears to happen before any GitHub-specific action, during Codex app-server startup/navigation. [email protected] is my account for codex