I've synced Spotify with my iTunes library (i.e. I've imported all my iTunes playlists to Spotify), but lots of the songs (maybe a quarter of the total) have not transferred successfullly. These songs show up in Spotify but are greyed out and when I click on them it says 'Track not Synced ' (on iPad) or 'This track was added as a local file. If you have the file on your computer you can import it.' (on my Mac desktop).

What gives? It's clearly not anything to do with the format of the files, as some songs from a single album won't play while others from the same album, downloaded to iTunes at the same time in the same way, will. Anyone know how to fix this? It's really annoying.

Thanks.

Andrew