Windows: Codex fails to start after update - bundled codex.exe returns "Access is denied" #40762

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

26.820.7780.0

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?

After updating the Codex Windows app to version 26.820.7780.0 today, Codex can no longer start.

It immediately shows:

“ChatGPT failed to start.
Unable to locate the Codex CLI binary.”

Codex was working normally before the update.

I confirmed that the bundled codex.exe still exists in the application package, but running it directly in PowerShell returns “Access is denied”.

The bundled codex.exe is also marked with the Encrypted file attribute.

It appears that the CLI file exists, but Windows cannot execute it after the update.

What steps can reproduce the bug?

1. Use a working Codex Windows desktop installation.

2. Update Codex to version 26.820.7780.0.

3. Launch Codex.

4. Codex immediately fails with:
   “Unable to locate the Codex CLI binary.”

5. Run the bundled CLI manually in PowerShell:

   $pkg = (Get-AppxPackage OpenAI.Codex).InstallLocation
   & "$pkg\app\resources\codex.exe" --version

6. PowerShell returns “Access is denied”.

The issue occurs every time Codex is launched after the update.

What is the expected behavior?

No response

Additional information

1. Use a working Codex Windows desktop installation.

2. Update Codex to version 26.820.7780.0.

3. Launch Codex.

4. Codex immediately fails with:
   “Unable to locate the Codex CLI binary.”

5. Run the bundled CLI manually in PowerShell:

   $pkg = (Get-AppxPackage OpenAI.Codex).InstallLocation
   & "$pkg\app\resources\codex.exe" --version

6. PowerShell returns “Access is denied”.

The issue occurs every time Codex is launched after the update.