I've had this problem with iTunes for a while, but it keeps on coming back just after I think I fixed it. What iTunes does is (almost instantly or over time) corrupts my mp3s, making the file sizes bigger for some reason, and this causes iTunes to not finish the tracks and jump around in the last 10 seconds or so (sometimes as long as an entire track). I called up Apple, and they've never heard this problem before. It's not like the mp3s are corrupted before this happens, because the songs are either CDs I've ripped by myself (and have worked in the past), or they're free from the artist (which would make no sense for an artist to corrupt their own mp3s). I've tried playing the corrupted mp3s in other players, and they still don't work. The only solution seems to be reimporting the tracks, but even then they sometimes get corrupted as soon as I put them in (like, I'll skip to the end once and it works, but once I add the artwork/info, it corrupts again). It seems to spread like a virus as soon as one album is infected, and I really need help/a solution. This is frustrating beyond belief. I also have the current version of iTunes, so updating won't help (and never has in the past).