I did a test to check how the app reacts.. So i imported 100 songs... Uploaded in drive (also synced my tablet).. Then i deleted some of the songs but in random... Then i went in the folder with my 100 songs and i import them again all of them (didnt knew what i deleted {that's why i deleted in random})... The app found correctly the duplicate files but it started analyzing all the files again (little bit faster i thing)... Not sure if it's a bug or this is how it works, but i found it strange to reanalyze all the songs, because i did that with 100 songs... If i do that in my all collection (20000+ songs), not sure if it really need to....