Hi, I just got done installing a new hard drive in to an iMac and used a portable hard drive when I use SuperDuper. Everything transfered without any problems. But now I want to erase the portable hard drive that contained all of the transfered data. What is the best way to erase that data so I can use the portable hard drive so I have a clean drive and can use it to back up with Time Machine?
If it was set up for SuperDuper, it should be Apple-format.
Go into DiskUtility, select the partition of the external in the left column, and you should have an "Erase" option at the top of the main-activity window. You can decide if you need more than simple "Erase" (you can do a 7-pass erase, but nromally that is used when transferring a disk to a new user/buyer).