How to Change the Disk in a Mac OS While Starting Up
- 1). Press the "On" button to power up your Mac.
- 2). Hold down the "Option" key on your keyboard. Wait for the Mac to start up and scan for other bootable disks. The Startup Manager opens, displaying icons of available drives from which you can boot.
- 3). Release the "Option" key.
- 4). Press the arrow keys on your keyboard to select the icon of the disk from which you want to boot. Press the "Enter" key to boot your computer from the selected drive.
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