hendrik on 20 May, 2020 07:18 AM
If a restart does not help, you can find the database folder by using Finder.
Choose Go -> Go To Folder
Then paste ~/Library/Application Support/beaTunes/ into the dialog. The ~ character is essential! (see attached screenshots)
There you will find a folder named Database. Simply rename it or delete it. beaTunes will then recreate the database based on your music files when you start it. This means, whatever data wasn't embedded in your files will be lost (see also here).