I bet this will also turn out to be very obvious...
Within \My Music I had a \Playlists subfolder containing all my old .m3u playlists (used mainly with Media Monkey). So by specifying \My Music as the folder for import, I've ended up with many hundreds of duplicate entries in the iTunes music library.
I've now moved that folder out of \My Music. But how do I get iTunes to recognise this and remove all the duplicate entries please? I sort of hoped it would do so automagically, but no!
Terry, East Grinstead, UK