What do you do if your mac crashes as while you're backing up using time machine?
Safe Boot from the HD, (holding Shift key down at bootup), run Disk Utility in Applications>Utilities, then highlight your drive, click on Repair Permissions, then Repair the backup drive, reboot when complete, test again.
Thanks BDAqua! How long should it take to back up? I have 125.25 GB altogether and it has taken all night to just 33.44 GB... Is the right?
It could be right, how is the drive connected... interface wise?
Open Console in Applications>Utilities & see if there are any clues or repeating messages when this is going on.
Retrieving data ...