How to Create a Backup Disk for the iMac
- 1). Insert the USB cable from the external hard drive to an open USB port on your iMac.
- 2). Click the "Time Machine" icon on the dock.
- 3). Click the "Use as Backup Disk" option, and Time Machine will use the hard drive to create a backup for all the files, including the operating system for your iMac.
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