Can I Downgrade My macOS from Big Sur To Catalina?

Yes, you can! There are many reasons why even if your recently downloaded macOS11 Big Sur, despite all it’s new advanced features and functionalities, you would prefer to downgrade and go back to macOS Catalina. Is this even possible? Yes, it is. As such, we put this title wide to help you downgrade your MacBook’s system without losing any valuable data in the process.


If you’re fully confident that Big Sur is not for you and you would prefer Catalina, then continue reading. Plus, luckily enough, it’s not even that difficult to do.


How To Downgrade to Catalina


There are primarily five main steps to accomplishing this. This includes backing up all your important data to actually restoring the previous macOS. Moreover, in order for you to downgrade your Mac’s system safely you will need to make use of Apple’s Time Machine feature or a third party back up application. But without any more delay, let’s dive into it.


  1. Backing Up Your Files


This is probably the most important step of them all. Even if you don’t have a lot of files on your Mac, it is still crucial that you back up all the content in your device. This is because when you downgrade, you are essentially erasing everything from your Mac’s hard drive. This means any work you were doing up until this point, will be erased completely. So, make sure that you create a bootable backup using either the Time Machine feature or a third party app like, Get Backup Pro, which will create a complete duplicate of your system hard drive, allowing you to continue working as before.


  1. Download The Previous macOS Onto A Bootable Drive 


The next important step is to create a bootable drive on an external drive where you will install Catalina. It is essential that you do this before erasing Big Sur from your Mac’s hard drive. You will have to undertake some work on the Terminal program, but don’t worry, it’s pretty simple.


The first thing to do, is make sure that your device will be able to be booted from external media. You can accomplish this by:


  1. Restarting Your Mac


  1. Boot in Recovery Mode (Hold Command + R buttons) once you see the Apple logo.


  1. Access Utilities > Startup Security Utility 


  1. Enter your firmware password


  1. In External Boot, tick the “Allow booting from external media” box.


After this, you can now get started on re-installing Catalina back into your Mac. You can do the by first downloading the Catalina installer form the Mac App Store. Keep in mind that Apple tends to remove the previous OS versions and replaces it with the latest one, so it’s best you do this as early as possible. Once downloaded, you can transfer the installer onto your external drive using a powered usb c hub. You need to also make sure that the drive has at least 12GB of available storage space.


Once you’ve cleared enough space, you also need to format the external drive. So, connect it to your MacBook then follow these steps:


  1. Finder > Applications
  2. Utilities > Disk Utility
  3. Erase Your Drive
  4. Select macOS Extended format


Once completed, you can then install Catalina on your drive by following these steps:


  1. Open Finder > Applications
  2. Head To Terminal
  3. Enter this command prompt 

sudo /Applications/Install\ macOS\ --volume /Volumes/MyDrive


NB: Keep in mind, that you should replace “MyDrive” with the name of your external drive, whatever it may be.


Once you’ve input the command, hit Enter and input your password when prompted. You can then confirm your choice by hitting Y. And it’s that simple. Once the program confirms the process is done, you can eject your drive from your Mac.


  1. Erasing Big Sur


This is finally the point in time when you can finally remove Big Sur and replace it back with macOS Catalina.


  1. Restart Your Device
  2. Reboot in recovery mode (Hold down Command + R)
  3. Open Disk Utility > Continue 
  4. Select your Startup Disk > Erase
  5. Select macOS Extended format
  6. Confirm


  1. Reinstalling Catalina


Once that is completed, you can finally re-install macOS Catalina by following these steps:


  1. Ensure you have a stable wifi connection
  2. Connect your bootable external drive using a usb c hub macbook pro
  3. Restart Your Mac and hold down the Option key at the same time
  4. You should see a list of startup disk options
  5. Select your bootable drive with the Catalina installer
  6. Continue and patiently wait for the OS to reinstall.


  1. Restoring Your Saved Backup Files


The final stage is to restore all of your saved data back into your Mac and you can easily put everything back using either your Time Machine backup or the third party app you used. You can restore your files through Time Machine by:


  1. Restart Your Mac
  2. Holding down Command + R to enter Recovery 
  3. Access Utilities
  4. Restore from Time Machine


If you used a third party app, then it should be even easier to restore your data as you only have to launch the app and follow the instructions to restore.




That summarises the whole process as simply as we could possibly do it. The instructions are pretty much general so it doesn’t matter what Mac you have, they will remain applicable. However, do remember that backing up your data is the most important part, so make sure you get that done first and foremost.

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