There’s also a way to select a startup disk immediately after you turn on your Mac. To change your startup disk back to the primary disk, repeat the instructions and select the primary disk as the startup disk. Select the hard disk or partition you want to use as the startup disk.Ĭlick Restart to restart your computer and boot from the selected startup disk. Here’s how to change your Mac’s startup disk:Ĭonnect the drive you want to use as a startup disk to your computer.įrom the Apple menu, select System Preferences. Changing Your Mac’s Startup Disk with System Preferences Normally, the startup disk is set as the hard disk inside of your Mac, but you can use an external hard drive, USB thumb drive, or DVD as your startup disk. When your Mac turns on, it loads the operating system on the designated startup disk, a hard disk or partition containing the macOS operating system. It is recommended that you choose the APFS disk format.AirPort Apple Apps Backups Developer Education Email Hardware Internet iPad iPhone Mac Music Network Photos Security TV Weekend Wonk Click the Erase button in the toolbar and specify the volume name and formatting. If there are several volumes, you can format them separately. Then select how many partitions you need, and specify the name, formatting and size for each of them.įormatting erases all data on your disk or a volume (depending on what is selected). To partition your disk, select it and click the Partition button. Choose GUID Partition Map to make the disk bootable. To choose the partition map scheme, select the disk (not a volume) and click the Erase button. It is recommended that you backup your data before making any changes. Partitioning can erase all data on your disk.

Its format will be indicated right below the volume name in the upper section of the main window.Īlso, you can click the Info button in the toolbar to get more details. If the sidebar displays only volumes, select the View > Show all Devices in the main menu. The partition map scheme is indicated in the table. Select your disk (not a volume) in Disk Utility. Finding out the current partition map scheme Finding out the current partition map schemeįor all tasks described here, use the Disk Utility application located in the Applications/Utilities folder.Cloning Disks Partitioning and Formatting your Disk

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