macOS Sierra

macOS Mojave is the next major operating system for Mac — but just because you take a new beta for a whirl doesn't mean you're ready to commit your daily driver to it just yet. If you've decided you'd rather return to macOS High Sierra, you can downgrade with just a few steps. If you follow these steps you'll be back to your old setup in no time.

Note: If you are reading this article on the Mac that you want to downgrade on, switch to another device or print this page before continuing so you can read along as you go.

Step 1: Back up your Mac

This process will erase macOS High Sierra from your hard drive entirely. That means any files, programs, or documents you've been working on while using macOS Mojave will also be erased if you don't back them up first. Use an external hard drive or a cloud-based program like DropBox, OneDrive, or iCloud. If you don't save these important files somewhere off of your computer you will lose them.

Step 2: Create a bootable drive of macOS High Sierra

Before you erase macOS Mojave from your computer, download macOS HighSierra from the Mac App Store. It should be in your purchase list, or you can simply search for it in the Mac App Store. You'll need a copy of macOS High Sierra in order to downgrade from macOS Mojave.

When the final version of macOS Mojave goes live, macOS High Sierra will no longer be available in the App Store, so make sure you download High Sierra before Mojave launches this fall.

Note: Making a bootable installer requires the use of Terminal. If you don't feel comfortable making changes to your Mac with Terminal, you can create a bootable disk using the DiskMaker X program.

Step 3: Erase macOS Mojave

  1. Connect your Mac to the internet via Wi-Fi or Ethernet.
  2. Click on the Apple icon in the upper left corner of the screen.
  3. Select Restart from the dropdown menu.

    Restarting Mac

  4. Hold down Command+R, and keep holding the keys until your computer reboots. This will put your computer into Recovery Mode.
  5. Click on Disk Utility in the OS X Utilities selector.
  6. Click Continue.

    Seleting Disk Utilities from the OS X Utilities Selector

  7. Select your Startup Disk.
  8. Click on the Erase tab at the top of the window.

    Selecting a drive to erase on Mac

  9. Enter a name for the file to be destroyed (Like macOS High Sierra or something).
  10. If your Mac is using HFS+, select Mac OS Extended (Journaled) from the format list. If your Mac is using APFS, select APFS from the format list.
  11. If Scheme is available, select GUID Partition Map.
  12. Click Erase.

    Erasing a drive on Mac

After the process is complete, quit Disk Utility from the dropdown menu in the upper left corner of the screen to go back to the OS X Utilities selector.

Step 4: Reinstall macOS High Sierra

After you have erased macOS Mojave, you will want to reinstall an earlier operating system.

NOTE: If your Mac came with macOS High Sierra, you can restart your Mac while holding down Shift-Option-Command-R to simply install the operating system that came with your Mac. Otherwise, follow the steps below to install High Sierra back on your Mac.

  1. Connect your Mac to the internet via Wi-Fi or Ethernet.
  2. Click on the Apple icon in the upper left corner of the screen.
  3. Select Restart from the dropdown menu.

    Restarting Mac

  4. Hold down Option while your computer restarts. This will send you to the option to select a startup disk.
  5. Select your bootable drive with macOS High Sierra from the list of startup disk options. macOS High Sierra will begin installing on your Mac.
  6. Click Continue in the macOS High Sierra installation window.

macOS High Sierra will install like a standard update. You will agree to the licensing terms before the software reboots on your Mac.

Step 5: Restore settings from an earlier macOS High Sierra Time machine backup

If you have a recent backup of your Mac saved via Time Machine (which you should), you can use it to reinstall the settings you have saved from macOS High Sierra.

  1. Connect your Mac to the internet via Wi-Fi or Ethernet
  2. Click on the Apple icon.
  3. Select Restart from the dropdown menu.

    Restarting Mac

  4. Hold down Command+R when you hear the startup chime and keep holding the keys until your computer reboots.
  5. Select Restore from Time Machine Backup in the OS X Utilities selector.
  6. Click Continue.

    Selecting restore from backup from the OS X Utilities Selector

  7. Click Continue after reading the important information about restoring from a backup.
  8. Select the Backup source for where your Time Machine backup is stored.
  9. Click Continue.
  10. Select the most recent macOS High Sierra backup on the drive.
  11. Click Continue.

    Steps to restore from backup on Mac

Your Mac will begin restoring from the Time Machine backup and then reboot. This process can take a while, so grab a cup of coffee while you wait.

If you run into any problems while trying to downgrade your Mac operating system, let us know in the comments.

macOS High Sierra

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macOS Sierra