Quick summary

On Windows, when the logged-in username is longer than 8 characters (e.g. "karngenie"), Windows generates an 8.3 short name for the user profile folder (e.g. "KARNGE~1"). Studio's open_basedir configuration mixes long-form and short-form paths for the same profile directory, causing PHP to fail resolving paths and crash the site with a fatal error. This happens even when the site itself is created outside the user profile, since the issue comes from Studio's own temp/AppData paths, not the site location.

Steps to reproduce

1. Use a Windows account whose username is longer than 8 characters (plain alphanumeric is enough — length alone triggers Windows' 8.3 short name generation).
2. Create a new site in Studio (reproduced both under the default C:\Users<username>\Studio... path and under a custom path like C:\Dev\Perso\wp...).
3. Start the site.

What you expected to happen

The site starts normally. Studio should consistently use either the long-form or short-form path when building the open_basedir list and any related include/require paths, so PHP doesn't fail to resolve legitimate paths due to a mismatch.

What actually happened

The site fails to start with:

Warning: Unknown: open_basedir restriction in effect. File(C:\Users\karngenie) is not within the allowed path(s): (C:\Dev\Perso\wp\mon-merveilleux-site-web;C:\Users\karngenie\AppData\Local\studio_app\app-1.13.0\resources\cli\php\router.php;C:\Users\karngenie\AppData\Local\studio_app\app-1.13.0\resources\cli\wp-files\phpmyadmin;C:\Users\KARNGE1\AppData\Local\Temp\studio-phpmyadmin-wp-env\4088db00-6c85-47e4-a038-c2a367ce9f59\wp-env.php;C:\Users\KARNGE1\AppData\Local\Temp\studio-phpmyadmin-sessions\4088db00-6c85-47e4-a038-c2a367ce9f59;C:\Users\KARNGE1\AppData\Local\Temp\studio-mu-plugins-d19RMd;C:\Users\KARNGE1\AppData\Local\Temp) in Unknown on line 0
Warning: Unknown: Failed to open stream: Operation not permitted in Unknown on line 0
Fatal error: Failed opening required 'C:\Users\KARNGE' (include_path='.;C:\php\pear') in Unknown on line 0

Note the open_basedir list mixes the long-form path (C:\Users\karngenie\AppData...) and the short-form 8.3 path (C:\Users\KARNGE~1\AppData...) for the same directory, and the fatal error tries to open a truncated/malformed path (C:\Users\KARNGE) that doesn't correspond to any real file.

Environment: Studio version 1.13.0, Windows, username length >8 characters (no special characters).

Workarounds found:

• Moving the site folder outside C:\Users... does NOT fix the issue, since Studio's internal temp/AppData paths still reference the affected profile folder.
• Disabling 8.3 short name generation (fsutil 8dot3name set c: 1) and removing the existing short name for the profile folder (fsutil file setshortname "C:\Users<username>" "") works around the issue but requires admin rights.
• Using a Windows account with a username of 8 characters or fewer avoids the issue entirely.

Impact

Some (< 50%)

Available workarounds?

No and the app is unusable

Platform

Windows

Logs or notes

No response