How to Dual Boot MacOS High Sierra Beta & Sierra on Partitions

The macOS High Sierra beta can be installed and dual booted alongside a stable release of MacOS Sierra, El Capitan, or another Mac OS X release. This can be a suitable option for developers, beta testers, and pro users who want to try out the new MacOS 10.13 beta release without overly committing to it, as it leaves the primary stable macOS release intact on the same computer and does not overwrite it. When finished, you will be able to boot between either the beta macOS High Sierra release, or the stable macOS release that already was on the Mac.

This is aimed at advanced users only. Do not modify a partition scheme or install any beta operating system without completely backing up the Mac first with Time Machine or your backup method of choice. Failure to backup may result in permanent data loss.

Remember, beta system software is notoriously unreliable, slow, and problematic, do not run beta system software as a primary operating system and do not install beta system software over any important data.

How to Dual Boot & Install macOS High Sierra Beta to Separate Partition

Note you can initiate this dual boot creation and install process from the current macOS installation, or directly from a macOS High Sierra beta USB install drive too.

  1. Back up the Mac, do not skip this step
  2. Download the macOS High Sierra beta installer from the Mac App Store (you will need to be enrolled in the beta testing program)
  3. Download macOS High Sierra

  4. Open Disk Utility on the Mac then choose the primary hard drive and go to the “Partition” tab
  5. Click on the + icon and create a new partition, give it an obvious name “High Sierra” or something similar, and assign it a reasonable amount of space (20GB or more) and click Apply to create the new partition
  6. Create a new partition for macOS High Sierra

  7. Quit out of Disk Utility
  8. Open “Install macOS 10.13” app from the /Applications folder (or choose the installer from the USB boot drive)
  9. MacOS High Sierra installer
    Install macOS High Sierra beta

  10. Go through the installation menus and at the disk selection screen choose “Show All Disks” and then specifically select the new partition you created a moment ago called “High Sierra” – do NOT install over your primary partition
  11. Choose show all disks to select MacOS High Sierra partition to install onto

  12. Install macOS High Sierra beta as usual, when finished macOS High Sierra will boot automatically

The process is pretty straight forward and is largely the same with macOS High Sierra as it was with most other Mac operating system releases.

Essentially this offers a way to test out the High Sierra beta without overwriting your primary macOS install, each operating system will be self contained on it’s own partition.

Switching Between & Booting High Sierra or the Other Mac OS Release

You can restart and switch between the beta macOS High Sierra release and the regular Mac OS installation anytime with either of these methods:

  • Choosing the volume to startup in  Apple menu > System Preferences > Startup Disk
  • OR by holding down the OPTION / ALT key on system start and selecting the boot volume and operating system to boot

You must reboot the Mac to switch between the High Sierra release and other system software.

Dual booting macOS High Sierra beta

How else can I dual boot macOS High Sierra 10.13 and a stable Mac OS release?

Another option would be to install macOS High Sierra onto a completely different hard drive, or with an external fast SSD drive, and boot from that too. That would be an even safer approach as it does not involve partitioning the primary volume at all.

How do I delete the macOS High Sierra Partition?

You can delete the macOS High Sierra partition at any time, all you need to do is boot into the other Mac OS installation and open Disk Utility, choose the drive and return back to the partition menu, then select the High Sierra partition and click the “-” minus button to remove the partition. You can also do this from a USB boot drive, or from recovery mode.

Do you have any questions, tips, tricks, or advice about dual booting High Sierra and another release? Let us know in the comments below!

Source: OSX Daily