How to downgrade from Big Sur to Catalina

Want to downgrade after upgrading to macOS 11 Big Sur? This article will guide you to safely downgrade from macOS 11 Big Sur to previous macOS versions without losing data.

Toolset for safe downgrading macOS

Setapp can easily switch between macOS versions, providing a range of applications that protect your Mac security and ensure data integrity.

Before deciding to uninstall Big Sur, check out some common macOS 11 issues and their solutions. The problem you are having may be on the list and can be easily resolved. Also, if you are running macOS Big Sur beta, please note that the public release released on November 12 has fixed most of the issues.

If you want to learn directly about how to uninstall Big Sur from your Mac, continue reading. The good news is that rolling back macOS updates is easy. Please follow the following guide.

Why downgrade macOS Big Sur?

While most users are better off using the latest version of macOS on their devices, there are some reasons why they might need to downgrade from Big Sur:

• You are testing software for macOS Catalina users
• You want to run an application that is incompatible with macOS Big Sur or has an error while running
• Do you think your device is too old or the storage space is not enough to run macOS Big Sur
• You just like macOS Catalina

How to gradually downgrade Big Sur

To better illustrate the process, downgrade from Big Sur includes five important steps – from backing up all files obtained after the upgrade, to restoring these files on macOS Catalina. You need to use some tools to safely downgrade: mainly backup utilities (Apple's native Time Machine or more advanced third-party applications like Get Backup Pro) and CleanMyMac X to keep the system tidy. Now, when everything is ready, let's get started.

1. Backup your data (very important)

Don't skip this step even if you've just recently upgraded and don't accumulate much data on macOS Big Sur. Downgrade means you will erase everything on your hard drive. So everything you've been working on since installing macOS 11 will be lost. Make sure you avoid the hassle and create a quick backup. You can do this with Time Machine, but we recommend using Get Backup Pro to create bootable backups. This will give you an exact copy of the drive, including all saved settings – so that you can continue from where it is interrupted.

Here is how to back up data before uninstalling Big Sur:

1. Open Get Backup Pro from Setapp
2. Click the plus button at the bottom to create a new backup
3. Name your backup project
4. Select the backup target, and if necessary, customize the settings
5. Select files, folders, and application data to add to the backup
6. Click "Start".

Before creating a backup, it is best to use CleanMyMac X for system cleaning. This way, you can avoid backing up unnecessary files and duplicates, thus running a smooth and fast backup process. Additionally, the app is usually a great tool to use at any time to delete any cluttered files. Trust me, your Mac has a lot of these files. Here is how CleanMyMac X works:

1. Open the app and click Scan
2. Wait for CleanMyMac X to complete the scanning process
3. If you want to delete all junk files, click "Run". If you want to manually select the file you want to delete, click "View"
4. that's all! You are ready for a clean backup.

2. Install macOS Catalina on the bootable drive

This may seem a bit counterintuitive, but before erasing Big Sur, you have to install macOS Catalina on your external drive. This requires some terminal operation and we will guide you later. Before this, make sure your Mac can boot from external media.

Allow boot from external media on a new Mac

If you have a MacBook Air, MacBook Pro, or Mac mini (2018 and newer models) with a T2 security chip, you may experience problems with the startup file. To avoid this, you should allow booting from external media before downgrading to Catalina:

1. Restart your computer and enter recovery mode (hold Command R after the Apple logo appears)
2. Visit Utilities > Start Security Utilities
3. Enter your firmware password (note that this is the password you use to enable the launch security utility, which is different from your administrator and Apple ID credentials)
4. In External boot, select the check box next to Allow boot from external media.

Once everything is ready, you can restore Catalina. First, download macOS Catalina from the Mac App Store in the usual way. While the installer for the latest macOS version is only available before a new version is released, you should do this as early as possible.

Then, install macOS Catalina onto an external drive. Start with formatting the drive (you can skip this step if you have a formatted drive):

1. Get an external drive with at least 12GB of free space
2. Connect it to your Mac via USB
3. Open Finder > Applications
4. Navigate to Utilities > Disk Utility
5. Click "Erase" next to the drive (make sure you name it if you have multiple drives)
6. Select APFS or macOS extension format > "Erase".

Install macOS Catalina onto a formatted drive:

1. Open Finder > Applications
2. Start Terminal from Utilities
3. Enter the following command

sudo /Applications/Install\ macOS\ Catalina.app/Contents/Resources/createinstallmedia --volume /Volumes/MyVolume

Note that "MyVolume" in the above command is your drive name, so you should change it accordingly.

1. Click Enter/Return
2. Confirm your operation by entering your administrator password > Y
3. Click Return
4. Once the terminal shows "Finished", you can exit and eject the hard drive.

3. Remove macOS 11 from hard drive

Now is the time to say goodbye. Here is how to downgrade Big Sur to Catalina by removing macOS 11 from your hard drive:

1. Click on the Apple logo and select Restart from the menu
2. Press and hold Command R to restart in recovery mode
3. Open Disk Utility > Continue
4. Select your boot disk > "Erase"
5. Select the APFS or macOS extension format and confirm your actions.

4. Reinstall macOS Catalina on your Mac

Next, downgrade by reinstalling Catalina on your Mac:

1. Make sure your Mac is connected to the internet
2. Connect your bootable external drive
3. Click on the Apple logo and select Restart from the menu
4. When Mac restarts, hold down the Option key
5. Once the boot disk option list appears, select the bootable drive with the macOS Catalina installer
6. Click "Continue" to agree to the license terms and wait for macOS Catalina to reinstall.

5. Recover data from backup

The final step is to restore all data you have compiled since upgrading to Big Sur. Again, backup is crucial as it will help restore your files and save settings. You can restore everything using the same tool you used to create backups.

Here is how to restore Time Machine backup:

1. After connecting your Mac to the Internet, restart the system
2. Press and hold Command R to enter recovery mode
3. Visit Utilities > Recover from Time Machine Backup > Continue
4. Select Backup Source > Continue
5. Select your backup > Continue
6. After Time Machine restores data from backup, your Mac will restart.

Recovering data is even easier if you use Get Backup Pro for backup. You just need to launch the application, select your backup from the list, and click "Restore". Select a custom location for the file and click the "Recover" button again. That's it. All your data and settings will be restored to macOS Catalina within minutes.

That's it. The above guide is available whenever you want to know how to restore to previous macOS. All instructions are very general, except that terminal commands should be adjusted when installing older macOS on bootable drives.

If your Mac slows down or experiences other abnormal behavior after downgrade, we recommend using iStat Menus for advanced system performance monitoring. This application will help you understand the root cause of the problem—whether it is a login, network issue, or disk activity—and resolve them accordingly.

iStat Menus is available on Setapp along with utilities like CleanMyMac X and Get Backup Pro. So you can use them for free from one place for 7 days. Hopefully this tool set will help you understand how to downgrade macOS Big Sur, and keep your Mac in perfect condition at any time.

How to downgrade from APFS to HFS

If you want to change the file system from a newer APFS to HFS, you can try downgrading by following these steps:

1. Go to Finder > Applications > Utilities > Disk Utility .
2. Click the View icon and select Show All Devices .
3. Select the container for the volume you want to downgrade and click Erase .
4. In the pop-up menu, select the format of the disk. Mac OS extension (log style) corresponds to HFS.

Click to erase .

Frequently Asked Questions

How to downgrade from macOS beta

This process requires two main steps – logging out your device from the macOS beta program and reinstalling the macOS you want.

To log out of the beta program, go to System Preferences… > Software Updates . Click the details under "This Mac has registered Apple Beta software program"... and click Restore default values ​​in the pop-up window to confirm.

Next, follow the steps above to reinstall the macOS you want.

How to downgrade macOS without Time Machine

To downgrade macOS without using Time Machine backup, you need to create a bootable installer. Get flash drive or other auxiliary volumes – Formatted as Mac OS extensions and have at least 14 GB of free space. Next, download the official installer for macOS you want to install (from the Apple website) on it.

Then, for an Intel Mac, plug your drive into a Mac that is connected to the internet, turn it on and hold down the Option key immediately. When you see a screen with a bootable volume, release the Option key. Select the volume with the bootable installer and click the up arrow or Return. In the Utilities window, select Install macOS and click Continue , and the screen will guide you through the process.

For instructions on Apple Silicon, visit Apple's official support page.

How to downgrade macOS without losing data

The best way to degrade without losing data is to create the latest Time Machine backup, or back up your important data using a third-party application like Get Backup Pro or ChronoSync Express.

If you reinstalled the new macOS without backing up important files, you can try to restore them using solutions like Disk Drill. But be aware that you are unlikely to be able to recover files that were overwritten during the reinstallation process.

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