All my tracks have been ripped in iTunes using the standard AAC encoder (128 kbps standard) and show as .m4a files. They certainly sound better (fuller) than mp3 and no .wav files! I haven't added many tracks since I purchased the professional and latest version so do you think I should delete the current program and download again? I'm happy to share the files I've got but wouldn't wish to mess up the system as Limewire seems very good. For me the best aspect of music sharing is to be able to download those songs that have been stuck in my head for years like 1960's TV themes. I find it a very useful catharsis!