How To

How to downgrade macOS Big Sur to macOS Catalina?

Using beta as an operating system can be quite a work due to numbers of bugs, errors, and numbers of other problems that come with it.

Even without beta, using a stable operating system and having absolutely no error at all is quite a rare thing. Not only errors or bugs but there are users who want to change their macOS Big Sur to previous version macOS Catalina, as they are not satisfied or are not familiar with the macOS or it is not what the user was looking for. Maybe users want the change due to system compatibility error.

No matter what the reason is if you want to move back to earlier versions of macOS. Then we will help you here.

This method is also helpful for users who have unstable or slow internet. Using the installer, you can download the macOS and install it on your system. The installer can also be used for the installation of macOS on other multiple systems.

Users who have upgraded their system from macOS Mojave or macOS Catalina to macOS Big Sur, we would recommend you to use it. as this is an effortless, quick, and secure method.

In this method, you will download the setup file of macOS Catalina and burn it on a USB drive. Then you will connect it to your system and perform the installation.

Related: How to install macOS Big Sur on VMware Workstation?

How to downgrade from macOS Big Sur to macOS Catalina

downgrade macOS Big Sur to macOS Catalina
downgrade macOS Big Sur to macOS Catalina

We know that macOS Big Sur has brought tons of new features that were not present in previous versions of macOS. A brand new interface, number of useful features, and changes in hardware support are all brought by the macOS Big Sur. Still, the stable macOS has not been released yet which makes most of the users downgrade to the previous version. Here is how we moved to the earlier version.

Things you need to do before the installation.

Before starting the procedure, we took a backup of our files. It is necessary as during the installation there is a chance that we might lose our data. We recommend you to have a backup of your necessary file on any external hard drive too. You can use the Time Machine app for the creating a backups of your files.

Get yourself a USB drive of at least 16GB of storage and make sure there is no important file in it. As we are going to format the drive. There is also requirement for an internet connection.

Related: How to install macOS Catalina on VMware?

First, we will need to download the macOS Catalina setup file on your system.

downgrade macOS Big Sur
system preferences

Click on the Apple icon given on the top left of your screen. Clicking on the icon will open different option. You will need to select the System Preferences which is just below the About this mac.

Now, a new windows will appear with numbers of different options. Click on the Software Update.

software update setting macOS Big Sur
software update setting macOS Big Sur

Opening the software update, you will see “Unable to check for update on your window”. On the left side, you will find Software Update and below you will find Details… (Written in blue). Click on Details…

restore to default macOS
restore to default macOS

By clicking on Details… a small pop window will appear. Select the Restore Defaults button on your screen.

System will ask for your login password. Insert the password in the given blanks and click on Unlock.

Now, either you can visit the official site of Apple or open your AppStore. Inside the AppStore type “macOS Catalina” and download it. Here your system will start downloading the setup file of macOS Catalina. This may take a while as the size of macOS is bigger than 8GB. So, wait a while until the setup file gets downloaded.

macOS Catalina in macOS Big sur
macOS Catalina setup in macOS Big sur

For some users a pop up might appear asking for “This copy of the macOS Catalina installer application is too old to be opened on this version of macOS”. Just click on Quit and check if you have already the macOS Catalina in your system by opening the launchpad screen.

Related: How to create a bootable USB Installer of macOS Big Sur?

Create macOS Catalina Bootable Drive using terminal

Create macOS Catalina Bootable Drive using terminal
Create macOS Catalina Bootable Drive using terminal

As we mentioned before you will need a USB of at least 16 GB of storage to boot the setup file, now connect your USB drive to your system. Insert the USB drive and change the name into a single word. Remember this is an important part, your USB shouldn’t be having two words as you cant burn macOS on a USB with two words name.

You can change the name by just clicking on the name of USB drive or right-clicking and choosing the Rename “Disk C” option. Makes the name a single word like external, USB, or anything that you like.

macOS Catalina bootable USB code
macOS Catalina bootable USB code

Now, open Terminal and paste the command line given below. Before running the command in the terminal make sure that you have replaced the path and drive name. Here you will need to replace the *** to the name of your USB drive.

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

Related: How to download and install macOS Catalina on your Mac?

terminal commands for bootable macOS Catalina
terminal commands for bootable macOS Catalina

Mac login password will be asked. Enter the password and run the command. A new line will appear asking to erase the USB drive. By pressing Y and return key you can continue to next which is to erase everything from your USB.

Wait for two to five minutes till the procedure gets completed. First the system will erase the USB then it will copy all the necessary files on USB.

Now your USB is bootable. You can find your bootable USB drive from the Finder sidebar and see the setup file. Now is the time to perform the installation.

Warning: Don’t remove your bootable USB drive or disconnect the power supply of your mac during the installation. As, performing such action can cause corrupt files, or might even make you perform the entire procedure from the start again.

Restart the system

Now is the time to restart your system. While your Mac start again, press the Option key until the drives appears on your screen. In the drivers menu on your screen you will find your bootable USB drive of macOS Catalina as well.

Click on bootable drive and soon you will be taken to macOS Utilities.

Related: Fix BiError Domain Error 3 on macOS Big Sur on Virtual Box and VMware

macOS Utilities

In macOS Utilities, click on the install macOS then Continue. Now, your installation of macOS Catalina will begin. During the installation, you might face such phases.

The Terms and Conditions of Apple will appear on your screen. Accept the terms and conditions and click on Agree. Doing such work will pop up a small window on top. Click on Agree to continue.

Now, the disk will appear on your screen. Choose the drive where you want to install the macOS. The loading screen will start and this may take a while. Then perform the rest of the installation.

Rest of the installations are easy and we are sure you can do it on your own.  

  • Welcome windows will appear, select your location.
  • Written and spoken language appears. Select preferred languages, input sources, and dictation.
  • Select your Wi-Fi network and continue.
  • Data & privacy and continue.
  • Create a computer account. Insert full name account, name, and password hint and continue.
  • Enable location services and continue.
  • Screen time and continue.
  • Choose your look

Congratulation, you have successfully downgraded from macOS Big Sur to macOS Catalina. Here your work is done, you can use your macOS Catalina now. You can also use the bootable USB of macOS Catalina for the installation on other systems as well. When all the systems are configured, you can then restore all of your necessary files using the Time Machine application.

About the author


Hey, it's your Admin. I am a tech enthusiast who is trying to improve his skills to help others. My goal is to provide solutions to different software and operating systems. If you are having any kind of problem with tech and need assistance then I am here for you.

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