Time machine won't work. I tried to move files over to my external HDD using time machine, it got through about 100GB then stopped and said "unable to complete backup an error has occurred while copying files to the backup volume". It then just stops working and i have to restart the backup again. There seems to either be one file or something that stops it from backing up but the time machine preferences are so limited i can't see what. Anyone have any ideas of the problem or how i can find out which files are being backed up.