How to downgrade from MacOS Catalina to High Sierra?

How to downgrade from MacOS Catalina to High Sierra

What is Catalina and why should I downgrade to High Sierra?

Catalina is an update to Apple’s MacOS. This update has caused much controversy for its user-hostile changes. Most notably, it breaks support for many peripherals that are essential to users who want to use their macs as they have in the past. The good news is that there is still an option to downgrade from Catalina back to High Sierra if you act quickly!

When you’re running macOS Catalina on your Mac it is highly recommended that you keep two backups of your data, one manually and one automatically since Apple’s Time Machine software only supports macOS Sierra which makes automatic backup not possible for this new operating system

For most users though updating to Macintosh Catalina was not too difficult even though some problems were reported. The simplest method is to manually downgrade from macOS Catalina to High Sierra and then try to overcome whatever issues you have encountered i.e., install the applications again or look for a newer version of them

Why should I downgrade to High Sierra?

Here are a few problems reported with MacOS Catalina:

  1. A couple of days after launching the update users started reporting that while everything worked smoothly there were still issues with some applications i.e., Google Chrome would crash when opening a new window
  2. Apple has removed 32-bit support so old software such as Final Cut Pro 7 and QuickTime Player 7 won’t install
  3. Siri is not compatible with macOS Catalina

What do I need before I downgrade?

You will need a backup of your data before beginning this process. As with any computer procedure, there is always the risk of losing data if something goes wrong so it is best to be safe than sorry by making sure you have all your files backed up somewhere safe before continuing with this article.

How do I downgrade from macOS Catalina to High Sierra?

Method 1:

  1. Get a copy of the 10.14 or 10.13 installer from this link
  2. Launch the installer, accept the EULA terms and click Continue
  3. Click Agree on the next screen
  4. Choose your disk where you would like to install macOS High Sierra if it’s different than your current operating system drive (note that down somewhere) then click Install
  5. Enter an admin password when prompted to start installing High Sierra – do not use your Catalina password!
  6. Wait for the installation to finish, once done, restart your computer to begin using High Sierra again! If you have any questions or concerns about downgrading from macOS Catalina back to high sierra, please contact our Apple technicians who will be able to assist you with your downgrade
  7. Upon reboot, you will be greeted with this beautiful screen (do not click anywhere)
  8. Please note that after downgrading to macOS High Sierra, you’ll need to re-install all of your App Store purchases one at a time! Don’t worry it’s easy and only takes a few seconds per app! You may also notice some sound effects still carry over from Catalina as well as other small bugs such as flakey WiFi passwords but those can usually be fixed by resetting your SMC.

Method 2:

You cannot downgrade from macOS Catalina to High Sierra using Time Machine because Apple does not allow you to do so, only iTunes can be used and it requires a USB flash drive or external hard drive that must be at least 16GB in size. The process might take an hour or two depending on how many applications, files, and folders you have on your computer

  1. The first thing we need to do is back up all our files just in case something goes wrong during the whole downgrade process. We would like to mention that every time we say “backup” we mean back up to your computer’s internal hard drive or an external one too. iTunes is not the only way to do this, you can use CrashPlan (which is better).
  2. Let’s start with creating that 16GB USB flash drive or external hard drive first by using our preferred method. We’d like to point out that it would be good if you delete at least some of your files just so it saves more space on your flash drive. It doesn’t matter what kind of file it is, either the application, picture, video, or archive format since they’ll all fit depending on their size and quality. You can download Disk Drill for free if you want to check the amount of storage that it has.
  3. Note: You can use a USB stick that’s already formatted to exFAT. If you are using Windows, Apple recommends this for macOS Mojave compatibility – so you will need at least 6 GB minimum for this method to work.
  4. Download the disk image file from the Catalina update page on Apple’s website so you have all files securely in one place locally. NOTE: Please look in the Updates folder in /Applications/Utilities/. It should be there by default unless Catalina was installed manually without updating beforehand (we highly recommend updating first). The updates folder is also hidden, but Disk Utility can reveal it or Command+Shift+G.
  5. If part of your computer is running macOS Mojave, you will need to disable System Integrity Protection (SIP). Go to the Recovery Menu by holding Command+R when macOS starts up. Click Utilities on the top bar and select Terminal. Type csrutil disable which returns Success if done correctly. NOTE: If this fails for any reason, do not proceed until you’ve completed this step! Disabling SIP breaks some security precautions that protect crucial parts of your operating system. You can also try booting into Safe Mode (hold Shift while starting up) and then disabling it there too although we cannot confirm whether it works or not.
  6. Now open Finder and click on Applications in the left sidebar, then open the Utility folder. Click on Terminal and type in
  7. -This file is hidden by default (to view it, open Finder > Preferences/Advanced > Show File Extensions) but it doesn’t need to be changed. Copy this file into your “downgraded” version of macOS High Sierra (select High Sierra from the sidebar to open it) and name it “InstallApplications”. NOTE: Change the location of where you save this file *before* you paste or type anything else! If done correctly, there will now be files in your Macintosh HD > Library > CoreServices folder.
  8. When macOS finishes installing, click on Continue through all of the prompts until you’re asked to restart your computer. Upon restarting you’ll notice that everything works like it normally does. If you’re asked to install macOS again, click on the Show Details button and then click Cancel Installation.
  9. Now that your Mac is working properly again (except for certain functions like Siri), go back into Recovery Mode by holding Command-R while your computer boots up. This time make sure you select the option in the top left corner menu labeled Reinstall OS X . NOTE: Your Wi-Fi won’t work until after this reinstallation process is complete, but that’s normal.
  10. Once macOS has finished installing, go through all of the prompts to set up your machine just like when you first got it. Make sure you don’t sign in with iCloud or any Gmail accounts!

What are the benefits of downgrading from macOS Catalina to High Sierra

There are many benefits of downgrading from macOS Catalina to High Sierra:

  1. You will be able to use your operating system as you have been used to for much longer
  2. The battery life of your device will again be high, but instead, it will be returned to normal conditions because an older kernel is being used.
  3. Most users reported that their websites were not working well on macOS Catalina’s Safari browser, especially if they are displayed in full-screen mode, something which makes web surfing much less enjoyable
  4. If you are experiencing any issues with permissions try downgrading from macOS Catalina to High Sierra
  5. While using High Sierra was pretty stable many users reported problems when using Apple’s latest operating system i.e., macOS Catalina has an issue with its Mail client where emails with embedded images, videos, or links may crash the application

Disadvantages of downgrading from macOS Catalina to High Sierra

There are some disadvantages of downgrading from MacOS Catalina to High Sierra as well:

  1. Support for macOS Catalina will be discontinued. So don’t downgrade expecting any new updates or fixes
  2. You can’t upgrade your Mac to macOS Mojave or future versions of macOS if you’re on High Sierra anymore, as Apple only allows users running the current version of macOS (e.g. macOS Mojave) to upgrade their operating system to a later version (e.g. macOS 10.14 Mojave)
  3. What if the downgrade fails? Well, you’ll be in trouble because all software updates from Apple will stop functioning and you’ll need to revert to macOS Catalina and start over to downgrade again.

FAQs for downgrading from macOS Catalina to High Sierra

Here are other frequently asked questions when users downgrade from macOS Catalina to High Sierra:

Should I use the Terminal to downgrade? 

No, it’s unnecessary. Please just follow the steps above. It’s way easier

Does this work on macOS Catalina 10.15 beta 3?

How long does the downgrading process take?

It should take about 20 minutes for an average user to downgrade from macOS Catalina back to High Sierra. This depends on the speed of the Mac being used, but it’s safe to say that even an Apple Watch will be able to handle this process without any problems.

Can I use the built-in App Store method and reinstall all my apps afterward?

Well, that is possible if you are using an external drive. If not, then no. You have to re-download all your apps from the Mac App Store .

Can I upgrade my Mac from High Sierra straight to Mojave?

No. The built-in Mac App Store mechanism will allow users to restore their Macs to macOS High Sierra, but no further upgrades are currently available through this method.

Besides downgrading, what other methods are there for me to downgrade a Mac running macOS Catalina?

Users who find themselves unable to complete the process of downgrading can also try out some other options, such as Time Machine or Clean Install. However, these are advanced procedures that require intense know-how on how they work and how to use them.

Can I go back to macOS Catalina if I change my mind?

Sure, Once booted into macOS High Sierra, you should follow the instructions on your Mac screen to upgrade your operating system back to macOS Catalina. In case that doesn’t work then back up everything using Time Machine and restore the backup once you switch back to macOS High Sierra If all else fails, you may need to get in touch with our friendly mac experts!

I am a computer engineer holding a bachelor's degree in Computer Science, complemented by a Master's in Business Administration from University of Strathclyde, Scotland. I currently work as a Senior IT Consultant in Melbourne, Australia. With over 15 years of...