Yesterday morning I started downloading a couple of 4 GB movies from the iTunes store. Yesterday night I checked on their status, and the progress bars in iTunes were almost complete - they both said they had downloaded well over 3 GB and there was less than 30 minutes remaining. Then a little later, I checked on their statuses again, and it looked like iTunes had decided to redownload both of the movies again, because both status bars were back at the beginning - they said they had downloaded around 20 MB or so, and there were several hours remaining. Finally this morning both movies finished downloading. Any idea why iTunes would start downloading the movies all over again?