Is the storage device to an external power supply?ĭepending on its model and power requirements, it may be necessary to connect your USB storage device to an external power supply. It will help troubleshoot any start up issues you may be plagued with. Should you run into problems whilst attempting to boot your Mac from an external storage device, consult our FAQ below. However, you can change that in System Preferences, or temporarily override it through Startup Manager.įull tutorial: how to choose a startup disk using System Preferences. Tip: Your Mac will now always boot into the selected startup disk. You will be presented with various disk icons.ģ) Select the system you would like to use to start your computer up.Ĥ) Now click the Restart button to start up your Mac using the chosen volume. You can use System Preferences to tell your Mac to automatically use optical media or an USB-based external disk or flash storage every time it’s restarted.ġ) Open the System Preferences application in the Dock.Ģ) Now click the Startup Disk pane.

How to start up your Mac from an external volume using System Preferences Tip: If there are several USB storage devices connected to your Mac, Startup Manager will only list the ones containing bootable volumes.įull tutorial: how to pick a startup disk for your Mac at boot time. Startup Manager will scan and list connected drives and volumes that can be booted from, as shown below.ģ) Highlight the volume you want to use by using your mouse or trackpad, or left and right arrow keys on the keyboard.Ĥ) Double-click or press the Return key to boot your Mac from the selected volume. Release the key after Startup Manager appears. If your USB thumb drive, USB external disk or flash storage contains a usable operating system or a macOS installer, you can select it at boot time using macOS’ built-in feature called Startup Manager, which can be invoked via a simple keystroke.Ģ) Press and hold the Option key immediately upon hearing the startup chime. How to start up your Mac from an external USB storage device Tip: You can easily burn a bootable image of macOS to a DVD using Disk Utility. You can also press the left mouse button on a wired mouse during startup to open the disc tray. Your Mac should start up from the macOS installer CD/DVD media. How to start up your Mac from a bootable CD/DVDġ) Firstly, turn on your Mac, or restart it if it’s already on by choosing Restart in the Apple menu.Ģ) Secondly, press and hold the C key on your keyboard immediately upon hearing the startup chime.

Bootable optical media (CD or DVD) on Macs equipped with Apple’s Super Drive or a USB thumb drive formatted with a GUID partition type and containing a macOS installer or a usable operating system.Īpple advises against booting from external storage containing a version of macOS earlier than the one your Mac shipped with.Starting up your Mac from an external disk requires the following:

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