I'm on a Late 2008 Aluminum Macbook running Lion (10.7.5). I finally got around to updating my AT2 to the newest software, 5.1 (5201). I was able to share my Macbook library okay, but iTunes (10.7) will not recognize the AT2 so I can't choose what music and photos to sync. I've been searching around for solutions for about an hour but none have worked. Any suggestions?