So I have an external harddrive that has a time machine clone of my internal 500gig drive. However, I just got a huge error on my internal drive, and had to reformat. After using migration assistant, everything is working. I want to use the time machine backup on the external, how do I do it? When I go to time machine, it finds the free space on the external (69 gigs) and uses that part as a new time machine backup. I find it very risky to format my old time machine backup right now because that'll only leave me a version of my files in my laptop (with the potentially faulty harddrive) What should I do? An option for me right now is to find another external, back up a timemachine on there. Then leave that as an archive backup, and then wipe my current external and use it as a regular backup.