I use an internal drive for Time Machine. It had been working fine for the longest time but now not so much. There is plenty of room left on the drive so I know it isn't a space issue. What happens is it will randomly fail when trying to back up. It will pop up a message saying that it has failed to back up, no other information. Other times it will work perfectly. I'm thinking maybe it has something to do with the hard drive sleeping, or the computer itself sleeping? I think it's happened while I was using the computer but I'm unsure. Thanks in advance for any help.