How to install the macOS Mojave public beta on a separate APFS volume

APFS makes it easier than ever to test drive a prerelease version of macOS. 

When you install the macOS Mojave beta on a separate volume of your hard drive, you can conveniently switch between Mojave and High Sierra on the same Mac, as if each were on a separate drive. And because the storage space used by the additional APFS volume is shared with your existing volume, you don't need to reserve space for the new volume. Its size automatically adjusts to fit your content.

What you need

To complete these steps, you need a Mac that has an all-flash storage device and macOS High Sierra. Make sure that you have at least 20GB of free space to install Mojave, plus any additional space needed for your files and apps. The space required to install Mojave and keep it up to date will vary throughout the beta release period.

Check About This Mac to see how much storage space is available, and check for ”Flash Storage” beneath the drive icon to confirm that you're using flash storage:

Storage tab of About This Mac

Choose Apple () menu > About This Mac, then click Storage.

If your Mac isn't using flash storage, you can create a new partition instead. In that case, follow the steps to add a volume to a device formatted as Mac OS Extended before continuing.

Back up your Mac

Beta software is software that is still in development, which means some apps and services might not work as expected. So it's important to back up your Mac before continuing. You can use Time Machine to make a backup

Add an APFS volume

  1. Open Disk Utility, which is in the Utilities folder of your Applications folder.
  2. In the sidebar, select your existing APFS volume. 
  3. Choose Edit > Add APFS Volume from the menu bar, or click the Add Volume button in the Disk Utility toolbar. These options are available only when an APFS volume is selected.
  4. Type a name for the new APFS volume, then click Add:

Disk Utility window, after choosing the option to create a new APFS volume. The Name field contains the words macOS Mojave Public Beta. The Format menu has APFS selected.

Enroll your Mac and install the beta

Go to and follow the instructions to enroll your Mac in the Apple Beta Software Program, download the Mojave beta installer, and begin installation.

When you're asked to choose where to install the beta, click Show All Disks and choose the volume you just created:

macOS Mojave 10.14 Beta installation window showing two volumes

Switch between Mojave and High Sierra

After installation is complete, you can use Startup Disk preferences or Startup Manager to quickly switch between Mojave and High Sierra:

  • Choose Apple () menu > Startup Disk, then click  and enter your administrator password. Select the Mojave or High Sierra volume, then click Restart.
  • Or press and hold the Option key during startup, then choose the Mojave or High Sierra volume when prompted.

Keep the beta up to date

When your Mac is enrolled in Apple Beta Software Program, you will receive a notification when a new public beta is available. To check for updates or install the latest version, use the Software Update pane in System Preferences:

Software Update pane of System Preferences

Choose Apple () menu > System Preferences, then click Software Update.

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