It is now possible to install the beta version of macOS Mojave - the new version of the Mac operating that will arrive for the general public this autumn. If you are a developer running the latest beta of macOS Mojave may be crucial for your business, but what if there are issues with the beta that render your Mac inoperable? In that case you can follow the steps below to revert to an older version of macOS.

As yet the macOS Mojave Public Beta isn’t available, but when it is there are bound to be a few people who dive right in only to regret it later on. Alternatively, you may be running a beta version of macOS High Sierra, and thinking that maybe you’d get more done if your Mac wasn’t installing a new, buggy, release of the software every two or so weeks. So we’ll also talk you through how to uninstall the public macOS beta too.

Note: it’s easier to downgrade from MacOS Mojave beta to High Sierra, or MacOS High Sierra beta to High Sierra, than it is to downgrade from High Sierra or Mojave to anything predating High Sierra. This is because Apple started using a completely new filing system (APFS) from High Sierra onwards - at least on SSDs (if you are using a Fusion Drive things are a little more complicated, we’ll look at that below.)

If you want to stop running the macOS Mojave beta, or macOS High Sierra beta, then read on.

If you are running a full version of Mac OS and would like to know how to downgrade from that, we have a separate article here: How to downgrade macOS.

What you need to do to uninstall the MacOS Mojave beta

There are a few ways you can revert to an older version of the operating system on a Mac.

  • You can create a USB Installer and do a clean install. This may be necessary if you are reverting from High Sierra or Mojave to an older version of the Mac operating system, as we will discuss below. We have a tutorial on How to do a clean install of macOS here LINK
  • You can download and install the OS using the built-in Internet Recovery (this could be the quickest method - if you web connection is good) But it all depends on what version you are reverting two.
  • You can also download the latest stable version of macOS High Sierra from the Mac App Store - this is the simplest way to revert from the beta.

Before you install the older version of the Operating System, make sure that you make a copy of all your important files (remember you won’t be able to recover files that Time Machine backed up since you were running the beta, so make a separate back up of these).

How to stop getting beta updates

If you want to run the final version of High Sierra, rather than the latest beta, you should start by stopping any future updates to the beta being pushed out to your Mac. To do this:

  1. Open System Preferences > App Store
  2. Click on the padlock in the bottom left in order to activate the Change button next to “Your computer is set to receive beta software updates”
  3. Enter your password
  4. Click on Change
  5. You’ll see the option to Stop showing beta software updates in the App Store.
  6. Choose “Do Not Show Beta Software Updates”.
  7. Click the padlock again

How to revert back to High Sierra from a beta via the Mac App Store

This process can take a while - and if you have an unreliable internet connection it may fail.

However, it’s the easiest way to install an older version of the OS.

  1. Open the Mac App Store.
  2. Click on Featured tab.
  3. In the “Quick Links” section on the right you should see High Sierra. Click on it.
  4. Now click on download.
  5. You’ll see a warning that you are downloading an older version of the OS, ignore it.
  6. Wait while the macOS downloads - it may take a while, and if your internet connection drops you might have to start again.
  7. Once it’s downloaded click on Open and wait while it installs. Expect this to take a while…

How to revert back to High Sierra from a beta using Time Machine

As with the method described above, this is a simpler way to install an older version of the macOS, of course you will need a backup from just before you installed the beta.

You will need the last Time Machine back up you made prior to installing the beta.

  1. Click on the Apple menu.
  2. Restart.
  3. Hold Option/Alt, Command + R until the Apple logo appears.
  4. Now you are in macOS Recovery, you’ll see the option to Restore from your Time Machine Backup. Click Continue.
  5. Note that when you Restore from Time Machine backup in Recovery mode the data on your Mac will be erased - so you will lose any data that you’ve created since installing the beta (so make a copy of this on a separate drive, or make sure it’s backed up in iCloud).
  6. Now you need to choose the right backup - the last one from before you installed the beta. (You can check this by looking at the macOS version column).
  7. Choose the back up and click on Restore.

Once restored any files you had created since the beta was installed can be transferred from the device you copied them to.

How to install High Sierra using a boot drive

This method will involve completely wiping your Mac, so make sure you have a back up made prior to installing Mojave (or at least copy any important files and photos to a separate drive to copy back later).

Follow these instructions to make a boot drive of MacOS High Sierra (or which ever version you wish to run)

Currently it is easy to download the latest version of High Sierra from the Mac App Store - but beware, once Mojave launches it will be a little more complicated. We have instructions for how to get an older version of the Mac operating system here.

Once you have your boot drive ready, follow these instructions to reinstall the older version of MacOS.

  1. Make sure you are connected to the internet
  2. Click on the Apple logo > Restart.
  3. Press Command + R until your computer reboots.
  4. When you enter Recovery mode click on Disk Utility > Continue.
  5. Select you Startup Disk.
  6. Click on Erase (yes, you need to erase your drive before you can continue).
  7. If your Mac is using APFS - likely if you were running High Sierra on a SSD, select APFS from the format list. In some rare scenarios your Mac might be using HFS+, if you have a Fusion Drive for example, in that case you’d need to choose Mac OS Extended (Journaled) from the format list.
  8. If Scheme is available, select GUID Partition Map.Click Erase.
  9. Wait for the Erase process to complete before you quit Disk Utility.
  10. Now, to install the macOS again… Make sure that the boot drive is plugged into your Mac.
  11. Click on Apple logo > Restart.
  12. Hold down Option/Alt while your Mac restarts.
  13. You’ll see a list of startup disk options, select your bootable drive containing macOS High Sierra.
  14. Click Continue and wait will High Sierra installs.

Now you can recover your setting and data from the last back up you made prior to installing the beta.

We have a guide to restoring from Time Machine here, but here’s a summary of the steps:

  1. Click the Apple logo > Restart.
  2. Hold down Command + R.
  3. Select Restore from Time Machine Backup.
  4. Continue.
  5. Select the Backup source.
  6. Continue.
  7. Find the most recent High Sierra backup.
  8. Continue.

What if you need to revert to Sierra or earlier?

As we said above, it’s a little more complicated if you are reverting from Mojave or High Sierra to a version of the macOS that predates them because Apple has switched to a new file system (at least on SSD-equipped Macs). You can expect Fusion Drives and Hard Drives to have a similar file system change in macOS Mojave.

When Apple stopped trying to make APFS work on Fusion Drives back when it was beta testing High Sierra (an early version of the beta did support it on Fusion Drives), the company issued the following instructions to downgrade from the APFS version to a HFS+ version.

It is possible that you may have to follow these instructions in downgrading if you are using a Fusion Drive or a hard drive as Apple has confirmed that it will be attempting to get APFS working on these formats.

  1. Make a Time Machine back up.
  2. Download the High Sierra install Assistant from the Mac App store.
  3. Create a bootable installer as above.
  4. Press Option/Alt as you start up your Mac.
  5. Choose the macOS High Sierra installer as your startup disk.
  6. Select Disk Utility.
  7. Choose Show All Devices.
  8. Choose your drive and click on Erase.
  9. Change the format to MacOS Extended (Journaled).
  10. Change the name of your drive to something else.
  11. Quit Disk Utility.
  12. Choose Reinstall macOS and select the new drive name as your target.
  13. Once in Setup Assistant choose to migrate your data from your Time Machine back up (Time Machine isn’t using APFS, yet, so this should work, for now).