Do you need to reconfigure Time Machine to use a new external hard drive? If you read my Tech Tips regularly then you’ll recall that I strongly recommend that everybody setup automatic and redundant systems to backup his or her Mac. If you use Time Machine to backup your Mac to an external hard drive then you either have or will replace the external drive when it dies. Here are instructions on how to reconfigure Time Machine to use a different hard drive.
Click on the Apple menu and select System Preferences
Click on Time Machine
Click the Select Disk button. [Note: If your Mac is configured to backup to 2 or more backup drives then the button will be labeled Add/Remove Backup Disk.]
In the Backup Disks section, click on the name of the external hard drive that has died and then click the Remove Disk button.
In the Available Disks section, click on the name of the external hard drive that is replacing the dead hard drive then click the Use Disk button.
Click the red dot to close System Preferences.
Within a couple of minutes, Time Machine will initiate a backup to this new hard drive. Let this backup run in the background. It’ll likely take many hours to finish since it needs to backup everything on your Mac.