I've been using one huge library for all my music located in two folders on the same drive, everything displaying and adding correctly. I tried to create a new library, containing only one folder of the two mentioned, added it to "Scan folders for new files". While scanning, the app showed correct number of tracks located in this folder. But when I closed and opened app, new music started to appear in this library, which is physically located in different folder (but included in my main library). Not every artist, feels like it's completely random. Re-did the whole process, and the same thing happened. Did the "rescan all files" in the advanced tools to no effect.