I have a rather large iTunes library (~16k files, 106 GB) and I notice that periodically iTunes loses track of a random selection of them (a couple hundred tracks at a time, usually entire albums go missing), necessitating either reimporting or locating the files individually, which is a huge pain in the rear. I was wondering if anyone else has had this issue, or if it was a known bug, and if there is a fix? Could it be that my library is stored on an external hard drive?