The Best way would be to Delete MM.DB and Start Over. There is no best way to clean library than delete it
o Windows XP:
C:\Documents and Settings\<USERNAME>\Local Settings\Application Data\MediaMonkey\MM.DB

o Windows Vista:
C:\Users\<USERNAME>\AppData\Local\MediaMonkey\MM.DB

Dear MM folks,

I just tried to delete a database, and it cascaded errors and flickered between them so badly that I had to write what happened in notepad, and type my email in notepad and paste the two into the databases and hold down alt-s to send the error reports (I am using the debug build). I meant to save the DB when MM finally crashed but after generating 20 or so errors it appears it managed to delete the DB. I will rebuild, and I can try deleting again if you want.

All I did was upgrade from an earlier build (3.0.6.something) and try to delete DB to rebuild it. You should have about 20 errors sent from me, maybe more. Let me know if I can do anything to help.

Andy