How to Downgrade from macOS Catalina to macOS Mojave Without Losing Any Data

Maybe macOS Catalina has triggered an unexpected battery drain on your Mac or maybe the software upgrade has slowed down your computer to a point where you can’t bear with the latest version of macOS anymore. Don’t worry, upgrading to the newest software has its share of ups and downs.

Having been in this situation many a time, I know how it feels like when all of your excitement of trying out new features come a cropper when you find your Mac struggling to keep up with the latest iteration of macOS. Fortunately, Apple offers a straightforward way to go back to the previous version. In this detailed guide, we are going to show you how you can downgrade macOS Catalina to macOS Mojave.

But before getting ready to downgrade your Mac, do not forget to back up your files or everything important to you right away as it will completely erase your device. The best and secure way to back up a Mac is to use Time Machine. To do so, head over to Apple Menu → System Preferences → Time Machine.

Also, ensure that you have the most recent backup of your Mac running macOS Mojave – just before you upgraded your device to Catalina. It will help you restore settings along with all the files you had. That all being said, let’s get started!

How to Downgrade macOS Catalina to macOS Mojave

Side Note:

  • Just in case, you have Macs equipped with T2 security chip (i.e. 2018 or later MacBook Pro, MacBook Air, or Mac mini), be sure to enable booting from external media. If Startup Security Utility is active on your Mac, ensure that you can use a bootable external drive. By default, the booting of external media is disabled.
  • To do so, restart your device → when Apple logo appears, hold down Command+R to put your Mac into Recovery Mode. Then, select Utilities in the Menu Bar and click Startup Security Utility. Now, enter your Administrator credentials and check the box to Allow booting from external media.

#1. Back-Up Your Entire Mac Upfront

It’s pretty easy to backup your Mac. Just make sure that you have your documents, files, pictures, etc produced or saved in macOS Catalina are safe in a hard drive. If you don’t have a hard drive, get yourself one from here! You can also try the cloud platforms to take your backup. Or if it’s too small or negligible, if just photos or videos, you can transfer it to your iPhone as well.

#2. Creating macOS Mojave Bootable Drive

Make sure you download macOS Mojave from the Mac App Store. Once done, you need to keep the downloaded file in an external hard drive to use it later on for the re-installation of macOS. If you aren’t aware of creating a bootable drive for macOS Mojave, check it out here to get started!

#3. Erase macOS Catalina from Your Mac

Now, it’s time to erase the Mac along with everything that’s stored on the device.

Step #1. Make sure that internet connectivity is good enough and it is connected to your Mac.

Step #2. First off, click on the Apple menu at the top left of the screen and choose Restart.

Step #3. Next, hold down the Command+R until your Mac reboots. Next, your macOS device will enter the Recovery mode. Select Disk Utility in the OS X Utilities selector and choose Continue.

Step #4. Up next, choose your Startup Disk and click on the Erase tab located at the top of the window.

Step #5. Now, you need to enter the name of the file you want to eliminate.

Sticky note:

  • If your computer is using HFS+, be sure to choose Mac OS Extended (Journaled) from the format list.
  • Just in case your device uses APFS, choose APFS from the format list.
  • One more thing worth reiterating is that if Scheme is available, make sure to choose GUID Partition Map.

Step #6.
Click on Erase to start eliminating everything stored on your device.

In the end, quit the Disk Utility from the drop-down menu in the top left corner of the screen to return to the OS X Utilities selector.

#4. Reinstall macOS Mojave

Once you have wiped out everything, get ready to reinstall macOS Mojave on your Mac.

Reinstalling macOS Mojave on the Macs That Came With Mojave Preinstalled

If your Mac had macOS Mojave preinstalled (at the time of purchase), all you need to do to reinstall Mojave is just hold down Shift-Option-Command-R to restart your Mac. Once your device reboots, Mojave will be live and running on your computer.

Reinstalling macOS Mojave on the Macs That Came With macOS High Sierra or Earlier macOS Version

If your Mac came with macOS High Sierra or earlier version of macOS, check out the steps below to reinstall macOS Mojave.

Step #1. Ensure that your Mac is connected to the Internet. Then, you need to connect the bootable hard drive (made with Mojave ) to your Mac.

Step #2. Now, click on the Apple menu in the top left corner of the screen and choose Restart from the drop-down menu.

Step #3. Next, you need to hold down the Option key while your Mac is restarting.

Now, you will get the option to choose a startup disk. Choose your bootable drive with macOS Mojave from the startup disk options.

Step #4. Now, macOS Mojave will start installing on your Mac. Hit Continue on the macOS Mojave installation window and then agree to the licensing terms and conditions.

#5. Restore Your Files From Latest macOS Mojave Time Machine Backup

Now that you have reinstalled Mojave on your Mac, restore all the settings along with the files from the earlier macOS Mojave Time Machine backup.

Step #1. Click on the Apple menu at the top left of your Mac screen and choose Restart.

Step #2. Now, press and hold Command+R keys the moment you hear the startup sound. Make sure to hold down the keys till your Mac reboots. Then, choose the Restore option from Time Machine Backup in the OS X Utilities selector and hit Continue.

Step #3. Next, click on Continue again once you have checked out the essential info about restoring from a backup. After that, choose Backup source and hit Continue.

Step #4. Make sure to select the most recent macOS Mojave backup on the drive and hit Continue one more time.

That’s pretty much it! Now, sit tight and allow your Mac to restore from the Time Machine backup.

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