How to create a dual boot in macOS

Many Mac users, when a new operating system is released, want to keep the previous version on their computer for a trial period that allows them to see how the new one responds with their regular applications.

Well, to have both operating systems on your Mac at the same time and enable dual booting, you don’t need too many requirements. In this article, we’ll walk you through how to configure your Mac so that it can start two versions of macOS.

Why set up macOS dual boot

There are a number of reasons why you might want to run two versions of the Mac operating system, which is basically what dual booting means.

• When you want to update your Mac to Software newer, but you have some legacy apps that we could run on the newer. Creating a dual boot could be a solution to test these applications in the new environment.
• If you are a developer of Software and you need to test your own apps on different versions of macOS.
• When you want to try a beta version of the Mac operating system without compromising or risking causing issues with the apps and data you have on your Mac.

Before we get into the details, there is one aspect of dual booting on Mac that we need to clarify. In earlier versions of macOS X and macOS, it would have been necessary to partition the Mac. In newer versions, the operating system creates a volume.

In this article, we’ll assume you’re running a newer version of macOS, so we’ll focus on creating a second volume for installation.

First steps

Before taking any action, you should keep the following in mind:

Make room. If you want to divide your Mac so that you can run two versions of the operating system, you will need space. Kill apps you don’t use, delete files and folders you don’t need, and copy your photo library to an external drive.

The next step will be to make a backup. It is always advisable to accomplish a task like this, in order to prevent something from going wrong. Consultation how to backup a Mac in a few simple steps.

Be prepared to delete everything. If you’re using an older version of macOS when you partition your Mac, you’ll need to erase it completely. If you want to keep your work, you need to create a backup of your Mac, so that the drive can be partitioned.

There are alternatives in this regard, such as the possibility of install the macOS version on a hard drive or external drive, by following the full tutorial.

How to create a new volume on your Mac

The method of creating a dual boot will depend on the version of macOS you are already using. If you have macOS High Sierra on an SSD, or have Mojave or Catalina installed, this process is much easier because your Mac will be using the Apple APFS file system.

APFS replaced the old file system: HFS +. In this way, APFS has a series of advantages, one of which is shared space usage, which allows you to share the available space between different volumes on your disk.

It is the way to have more space at all times, and basically, to forget what is assigned to each partition.

If you are using APFS, you can create an APFS volume as we will show you below and then just install the new version of the operating system on that volume. You won’t need to reformat anything. It couldn’t be easier.

If, on the contrary, you are using an older version of macOS, or even Mac OS X, it is a little more complicated, but we will also see this process in the article.

How to create an APFS volume

1. Make a backup of your Mac (as it’s always a good idea to do so before performing a task like this).
2. Open “Disk Utility” (you can find it in the “Utilities” folder under “Applications”, or just press “Command + Space” to start typing “Disk Utility”).
3. Click on the drop-down menu next to the “Show” button in the toolbar and choose “Show all devices.” This will ensure that you can see the volumes on your disk. You probably have one called Home.
4. Select the boot volume and click the “+” button to create a new volume.
5. Now you need to give your volume a name. If you are testing a new beta of the operating system, this might be the word to recognize it better.
6. You can set the storage limit if you want (although it is not necessary). To set a limit, click on “Size options” and complete the minimum storage quota options.
7. Now click “Add” to add the new volume to your Mac.

Once your second volume is operational, you’re ready to install the new beta or operating system of macOS.

If you are using an older version of the Mac operating system and you don’t have APFS, you will have to go through a slightly more complicated process that involves creating a partition. Let’s see how to do it next.

How to install macOS Big Sur on an APFS volume

Back in the days when macOS Big Sur was in beta, all you had to do was sign up for the ‘Apple Beta Software Program‘and follow the installation instructions.

Now that the final version has been released, when the installer window opens and you are prompted to choose where to install it, click “Show all disks” to select the new volume.

Once the new version is installed, you can shut down your Mac to force the computer to show you the dual boot menu. Here there can be two modes depending on whether your Mac is a new one with an M1 chip, or if you have one with an Intel processor.

• Mac Apple Silicon M1: Turn on your Mac and hold down the power button until the Startup Options window appears, showing a gear icon titled “ Options. ” Select and click “Continue”.
• Intel Mac: Make sure your Mac has an internet connection. Turn on the computer and hold down the ‘Command + R’ keys until you see the Apple logo.

If you are prompted to select a user whose password you know, select it, click “Next” and enter the administrator password.

How to install a second macOS system on a partition

If your Mac computer is a bit older and you haven’t reached the APFS world yet, you’ll need to split the primary hard drive into two separate drives, then install macOS Catalina on one partition and the other version of macOS on it. ‘other.

1. Start macOS in “Recovery Mode” (turn on your Mac and hold down the “Command and R” keys until you see an Apple logo or a rotating globe).
2. Once in recovery mode, use “Disk Utility” to clean the primary hard drive and divide it into two partitions.
3. Now get your ‘Time Machine’ backup on this partition. Keep in mind that you won’t be able to recover a backup that’s based on a newer version of macOS than the one you want to use on that partition.
4. You can also use the “Install on recovery” option to install the version of macOS you want to run on the primary partition.
5. Now it’s time to install the other version of macOS on partition 2. Follow the steps to install a second version of macOS, or the beta version of the new version of macOS, on the second partition.

Finally, we leave you a link to an article in which we explain how to recover a Mac with booting problems. You might also be interested in knowing how to reinstall macOS if recovery mode doesn’t work.