A Mac system can be booted from bootable media instead of the primary startup disk due to certain situations such as troubleshooting fault, partitioning, repairing disks, update, reinstalling the operating system, or even format everything. This post will cover two ways of starting up your Mac system from bootable media.
To this end, you will need a bootable drive, whether it is a mirrored external drive or a USB installer drive for earlier versions of Mac. Any Mac system will be able to startup from Recovery partition using the Boot Manager whether it is running on Lion (10.7) or later versions.
Before we go into details on how to start up your Mac using Startup Disk preferences, let us take a look at the meaning of startup disk.
A startup disk can be described as a partition of a volume or a drive containing a usable OS. It is important to emphasize here that your startup disk may not necessarily contain the Mac operating system.
For instance, if you are using Boot Camp, your Mac system can boot into Windows directly. Similarly, your Mac can also boot into any other OS, provided your Mac's hardware supports the operating system. You have the choice of setting your computer to either automatically using System Preferences or overriding the System Preferences using Startup Manager at boot time.
Starting up your Mac using preferences means instructing your system to automatically use bootable media each time the system is restarted. Here's how to start up your Mac using preferences;
Step 1 Open system preferences app in the Dock
Step 2 Click on the Startup Disk pane. After clicking the startup disk pane, various disk icons will pop up
Step 3 Now, select your preferred drive of startup your Mac
Step 4 After selecting your preferred drive, restart your system
Step 5 Your Mac will restart using the chosen drive
Note: The computer will only boot using the selected devices unless you make a change from the System Preferences or using the startup manager to override it.
If the chosen device has been disconnected from your Mac, a question mark may appear on your screen during the next boot time. This is because the chosen device has been disconnected. If the question mark appears too often, then the only remedy is to press and hold the OPTION key and then start the whole process of startup your Mac using preferences all over again to select the proper startup device.
The startup manager is an inbuilt application in which a computer user can invoke to choose a startup device during boot time.
There are several reasons why a computer can be started using a startup manager. Some of the reasons are;
Now, let us explained how to startup your Mac using the startup manager. The following are the steps involved in starting up a Mac computer using a startup manager;
Step 1 Press and hold the OPTIONAL key as soon as you restart or power on your Mac
Step 2 As soon as the window pops up, release the OPTIONAL key. If your system is protected with a password, enter the password and release the button
Step 3 Now, select the startup disk and then click on the device's icon. Please note that if you hold down the control button at this stage, the selected device would be saved in your system preferences. Therefore, it will persist unless you change or override the device.
If your disk doesn't appear in Startup manager or Startup disk preferences, you should check for the following possibilities;
For security reasons, Mac computers that are updated in terms of software do not display boot media that have the option of ROM firmware. This security feature can be disabled on Mac computer models earlier than 2015 and beyond to automatically load Option Firmware.
Here is how to go about it;
If the firmware on your Mac is password safe, it may not automatically load the ROM firmware due to additional security reasons. You can disable the additional security by following these steps;
There are other ways to start up your Mac computer apart from the above-mentioned methods. Other ways to start up your Mac computer include;
Safe mode: To simplify the process of troubleshooting those problems that are associated with your macOS, it is ideal to start up your Mac in a safe mode. Starting up your Mac in a safe mode will disable some features and then make only important components to load. Also, safe mode ensures that the startup disc is automatically checked and then resolves any issues with the startup process.
Verbose Mode: The verbose mode displays the progress of the startup process in a text format. You can leverage the verbose mode to resolve any custom hardware and kernel extensions related problems. Also, the verbose mode displays how the macOS loads its components.