macOS Sierra is almost here, but you may not be in love with the changes. You can partition your Mac and keep your current OS X right beside the new operating system.

macOS Sierra public launch is just around the corner. If you want to keep your current OS X operating system on your Mac, you can still run Sierra in tandem by partitioning your hard drive. We'll walk you through using the built-in Disk Utility software to split your hard drive and install macOS Sierra separately so you can keep both operating software programs running at the same time.

What is a disk partition?

Partitioning your Mac is basically splitting your hard drive into separate, usable systems. It makes it possible to run two separate operating systems on one device, like Windows and OS X, or El Capitan and macOS Sierra.

It is important to note that partitioning your hard drive also splits up your available hard drive space. Each partition will take up a portion of your usable storage. So, if you are running low on storage capacity on your hard drive, we don't recommend partitioning; try using an external drive, instead.

Before you start

The most important thing to do before making any changes to your hard drive is to back it up. Seriously. Back it up. Please. Time Machine is the easiest way to back up your data if you don't already have another system in place.

Make sure you have enough free disk space to properly run Sierra. Shoot for at least 30GB free.

How to create a partition on your Mac

  1. Open Finder from your dock.
  2. Select Applications.

    Selecting Applications in the Finder window on Mac

  3. Scroll down and open the Utilities folder.
  4. Double-click to open Disk Utility.

    Selecting the Disk Utility app on Mac

  5. Select your hard drive in the Disk Utility window. It will be the first drive on the list. It might be named "Fusion," or "Macintosh HD."
  6. Click on the Partition tab.
  7. Click the plus (+) button.

    Selecting your hard drive on Mac

  8. Change the size of the partition you wish to use by dragging the resize controls. The used space is represented in blue.
  9. Name the new partition.
  10. Click apply.

    Resizing and naming the new partition on Mac

Disk Utility will check the disk and make changes. This will take several minutes.

How to install macOS Sierra on your partitioned hard drive

Once your drive is partitioned, download macOS Sierra on your main partition first. Then, choose the partition when you get to the installation step.

  1. Download macOS Sierra on your main partition.
  2. Select Continue when the download is finished and ready to install.
  3. Agree to the terms.
  4. Click Agree to confirm that you have read the terms.

    Installing a beta on Mac

  5. Select Show All Disks to switch from your main partition.
  6. Select the partition you wish to install the beta on.
  7. Click Install.

    Changing partition installation on Mac

The installation helper will allow you to transfer information from your current OS X operating system, or you could choose to do a clean installation to start your Mac from scratch.

How to switch partitions

Your Mac will automatically restart using the beta partition. If you want to get back to your OS X install, however, you'll have to use the Startup Disk app to switch partitions.

  1. Click the Apple icon () in the upper-left corner of your screen.
  2. Select System Preferences... from the dropdown menu.

    Open system preferences on Mac

  3. Select Startup Disk.
  4. Click the Lock in the lower left corner of the window to unlock and make changes.

    Selecting startup disk on Mac

  5. Enter your system admin password.
  6. Click OK.
  7. Select your main hard drive.
  8. Click Restart.

    Restarting Mac

You can also restart your Mac and press the Option Key when you hear the startup chime. This will take you to the Startup Manager and you can select your drive from there.

Any questions?

Do you have any questions about installing a partition or downloading macOS Sierra onto a partitioned drive? Let us know in the comments.