There are a few ways to back up an external hard drive on a Mac.
One way is to use Time Machine, which is built into MacOS. To use Time Machine, connect the external hard drive to the Mac and open the Time Machine preferences. Select the external hard drive as the backup destination, and click the “Use for Backup” button. Time Machine will start backing up the drive automatically.
Another way to back up an external hard drive is …
Can Time Machine Backup External Drives?
Yes, Time Machine can backup external drives. In fact, Time Machine can backup any drive that is connected to your Mac. This includes drives connected via USB, Thunderbolt, FireWire, or Ethernet.
One thing to note is that you cannot use an external drive as a Time Machine backup if the drive is encrypted. Time Machine will not be able to read the drive if it is encrypted.
If you have a lot of data …
