My Time Machine drive started going crazy on me. Backups were failing...the drive (a Seagate FreeAgent Go) was making strange chirping noises. I ran Disk Repair and ended up getting this error: Invalid Key Index I ended up reformatting the drive. Things seem to be going fine right now. Can anyone tell me if this was just a filesystem error (which would hopefully have been fixed by my reformat) or is it a more serious hardware error? In short: do I need to get a Seagate RMA?