See Unity Issue Tracker - ERROR WHEN CHANGING QUALITY SETTINGS
Issue #8 was marked as a duplicate of this issue.
Possible fix: Auto Restart of Application.
Postpone the graphics settings change until the application is restarted.
Forgot using PlayerPrefs.Save().
Missing Textures are not fixed.
Changing Texture Quality might be set via PlayerPrefs and used on startup again. Applying shadows only.
→ <<cset c09dd4bf2cf6>>