It works well when troubleshooting problems with your Mac, especially if you can’t boot from the primary hard drive to access System Preferences. This is an easy way to select a startup disk before your Mac turns on.

Your Mac will boot from the startup disk you selected. Click the arrow directly below the drive.Select the disk you want to use as a startup disk.A screen displaying all of the available startup disks appears. Immediately press and hold down the Option key.Press the power button to turn on your Mac.Once you download and launch the app, click on a drive and the app will start scanning it. Connect the drive you want to use as a startup disk to your Mac. Disk Wave is an easy and free way to find out whats eating up your storage.For the past couple of days, Ive been getting the message that Im unable to save/download something because the startup disk is full. There’s also a way to select a startup disk immediately after you turn on your Mac. Macbook says 'Startup Disk is full' but it isnt full. 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. AirPort Apple Apps Backups Developer Education Email Hardware Internet iPad iPhone Mac Music Network Photos Security TV Weekend Wonk Startup disk really isnt full Since updating to Mavericks, Ive been getting the 'startup disk is full' message as well.

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