Problem:
Being new to SS and PHP I recently created a SS3 site hosted at my web hotel. After successful installation I edited the homepage and created a Content Editor user. After logging into admin with that user I get a white screen with the SS logo and nothing more happening. This now also goes for the default admin. The site itself seems fine, only admin affected. I currently have no error message or PHP logs to show, since this is on an externally hosted site.
Workarounds:
Enabling dev mode in _config.php, I can get it to work. But test and live modes gives the white screen with logo.
Reinstalling on top of the same site temporarily fixes the problem until that user logs in