Windows app fails to start for usernames with non-ASCII characters (Swedish Ä) due to malformed CODEX_HOME path

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

OpenAI.Codex 26.325.3894.0

What subscription do you have?

Pro plan

What platform is your computer?

Microsoft Windows NT 10.0.26200.0 x64

What issue are you seeing?

The newly released Codex Windows app installs successfully but fails during startup on a Windows account whose username contains a non-ASCII character.

On this machine, the app shows:

EPERM: operation not permitted, mkdir 'C:\Users\�GARE\.codex\sqlite'

So the app appears to mis-decode the username (ÄGARE becomes �GARE) when constructing the Codex home path, then tries to create an invalid path and aborts during bootstrap.

<img width="1422" height="657" alt="Image" src="https://github.com/user-attachments/assets/f5bf5c0d-afee-4cbb-bb66-321e27371f80" />

What steps can reproduce the bug?

1. Use Windows with a user profile path containing a non-ASCII character, for example C:\Users\ÄGARE.
2. Install the Codex Windows app from the Microsoft Store / Codex Installer.
3. Launch the app.
4. Startup fails before the main UI loads.

What is the expected behavior?

The Windows app should start normally for user profile paths containing Unicode characters, including Swedish characters like Ä.

Additional information

What I verified locally:

• The app package installs successfully.
• The CLI works and can read/write under C:\Users\ÄGARE\.codex, so this is not a general filesystem limitation.
• The packaged Windows app fails during bootstrap with:

EPERM: operation not permitted, mkdir 'C:\Users\�GARE\.codex\sqlite'

• A working local workaround is to set an ASCII-only override:

CODEX_HOME=C:\Users\GARE~1\.codex

• After setting that environment variable, the Windows app launches normally.

This strongly suggests a path/encoding bug in the Windows desktop app when deriving CODEX_HOME from the Windows user profile path.