How to Downgrade macOS Monterey/Big Sur to Catalina or Earlier

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Jerome Mills

5 min read

It's tempting to update to a new macOS. But when you upgrade, you may regret it. Common reasons include incompatible software, too many bugs, and your Mac running slow. Installing a new version of macOS is easy, but downgrading is more complicated. In this article, we'll show you how to downgrade macOS Monterey or Big Sur to an earlier Catalina, Mojave, High Sierra, or Sierra in 3 Ways.

How to Downgrade macOS Monterey/Big Sur to Catalina or Earlier

Back up Your Mac

First things first, you should back up your Mac. When you reinstall a macOS, all the data on your Mac will be wiped out. If you have backed up the things that are important to you, you can restore them quickly after reinstalling macOS.

How to Downgrade to the macOS That Came with Your Mac

If you are running High Sierra or a later version of macOS and want to downgrade it to the version that shipped with your Mac when you purchased it, you can quickly do it through Mac's built-in macOS Recovery feature. You just need to make sure your Mac is connected to the network. Here're the steps:

  1. Close and restart your Mac.
  2. Hold down the Shift + Option + Command + R until you see the macOS Utilities.
  3. On the macOS Utilities screen, select the Reinstall macOS option.
  4. Click Continue and follow the instructions on the screen.
  5. Select your startup disk and click Install. 
  6. Your Mac will restart after the installation is complete.

Reinstall macOS That Came with Your Mac

How to Downgrade macOS Using Time Machine Backup

Another way to downgrade your macOS is to use Time Machine Backup, but only if you have already backed up your previous macOS with Time Machine.

Here's what you need to do.

  1. Start your Mac and immediately hold down Command + R to start up from the built-in macOS Recovery system.
  2. Keep holding these two keys until you see the Apple logo or other image.
  3. In the macOS Utilities window, select Restore from a Time Machine backup and click the Continue button.
  4. Select your Time Machine backup and click on Continue.
  5. After the reinstallation process is complete, restore the files you backed up.

Downgrade macOS with Time Machine Backup

How to Downgrade macOS Using a Bootable Installer

What if you don't have a Time Machine backup but still want to revert to an earlier version of macOS? Do not worry. We'll show you how to install a downgraded macOS by using a bootable installer. This method is more complicated than the two methods mentioned above. To help you understand better, we've divided the steps into 4 main parts. Let's have a look now.

Part 1. Prepare an External Drive

You need an external drive of at least 14GB. Although macOS is about 12GB in size, you still need some extra space to store data. So please make sure that your external drive has enough space.

There might be other files in your drive. You'll need to format it.

  1. Plug your hard drive into Mac.

  2. Open the Disk Utility app via Spotlight.

  3. Select your drive in the sidebar and click the Erase button at the top of the window.

    Erase External Drive

  4. Name your drive as myVolume and choose a format your Mac supports from the Format drop-down menu. 

    • If your Mac uses HFS+, choose Mac OS Extended (Journaled).
    • If your Mac uses APFS, choose APFS.
  5. If the Scheme is available, select GUID Partition Map.

  6. Click the Erase button and then click Done.

Format External Drive

Part 2. Download macOS Installers

If you have previously downloaded the version of macOS you are going to install, you just need to open the Apple Store and download it again.

If you want to downgrade to a version of macOS that you haven't downloaded before, you won't be able to download it in the Apple Store. At this time, you can refer to this article.

Part 3. Create Your Bootable Installer 

Now you have prepared the external drive and macOS installer. Let's create your bootable installer.

  1. Connect your formatted hard drive to your Mac.

  2. Open the Terminal app.

  3. Enter and run a command like below. (The command will vary depending on your version of macOS. Let's assume that the installer is located in your Applications folder and myVolume is the name of your external drive. If your drive has a different name, replace "myVolume" with the name of your external drive.)

    • Big Sur: sudo /Applications/Install\ macOS\ Big\ Sur.app/Contents/Resources/createinstallmedia --volume /Volumes/MyVolume
    • Catalina: sudo /Applications/Install\ macOS\ Catalina.app/Contents/Resources/createinstallmedia --volume /Volumes/MyVolume
    • Mojave: sudo /Applications/Install\ macOS\ Mojave.app/Contents/Resources/createinstallmedia --volume /Volumes/MyVolume
    • High Sierra: sudo /Applications/Install\ macOS\ High\ Sierra.app/Contents/Resources/createinstallmedia --volume /Volumes/MyVolume
  4. Enter your password and press the Return again.

  5. Follow the instructions that appear in the Terminal.

  6. When you see Done in the Terminal, exit the Terminal and eject your hard drive.

How to Create a Bootable Installer

Part 4. Install macOS with Your Bootable Installer

Finally, you're ready to install your macOS.

  1. Plug your hard drive into Mac. (Make sure you have an internet connection.)

  2. Click the Apple icon > Restart.

  3. If you're using an Intel-based Mac, hold down the Option/Alt key until you see the Startup Manager window. If you're using an M1 Mac, hold the power button while rebooting Mac.

  4. Click on your external drive to select it as your startup disk. Your Mac will start up in Recovery Mode.

  5. From macOS Utilities, select Disk Utility.

    disk-utility-macos-recovery-mode.png

  6. Erase everything on your Mac and quit Disk Utility.

  7. Select Reinstall macOS > Continue.

  8. Follow the instructions to install your macOS with the bootable drive you created.

Conclusion

That's all for how to downgrade macOS to an earlier version. Do back up your Mac before downgrading your macOS. 

If you downgrade macOS because it is slow, you might as well use a cleaning tool like BuhoCleaner to clean up and speed it up. Click here for more Mac cleaning tips.

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