If you feel like testing the features of Catalina or wanting to develop and deploy apps for beta software and also not losing the versatility, smoothness and battery life of Mojave when at need, you can have both operating systems installed on your Mac, and because of the magic of the new file system introduced 2 years ago, APFS, your storage space is shared across volumes.

So you are probably wondering how to accomplish this? Don’t worry I’ve got you covered 😉.

Before we begin, it’s always a good idea to have a backup of your Mac, after all you are installing beta software, that is still in development, nobody knows what could go wrong so it’s better if you are covered.

Now we can begin!

Step 1: Add new APFS volumes

Open Disk Utility, select your current volume and add a new container to it by pressing the plus button. Give it a descriptive name like macOS Catalina Beta and press add. You should be able to see the new volume in the sidebar.

Halfway there!

Step 2: Install new version of macOS

You will have to enroll in the Apple Beta Software Program and then run the installer, when you are asked to choose where to install pick your new volume.

We are done!

Switching between macOS versions is as easy as it gets, during the startup procces press and hold the option key ⌥ until you are prompted the 2 volumes.

Here’s the original tutorial from Apple.

Thanks for reading, if you found this article useful or found an issue with it, please let me know so I can improve the quality of future writings and findings.