Reinstall Catalina From Big Sur

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Recently switched to macOS 11 Big Sur? This means you’re in for some huge enhancements and a completely redesigned look. It's fair to say Big Sur is not a perfect fit for everyone, though. Can you go back to previous macOS if that's the case? Sure. In this article, we describe how to downgrade from macOS 11 and continue using your previous macOS without any data loss.

  1. Before you can uninstall Big Sur, you first have to install macOS Catalina on an external drive. Some older models of Mac that do not use M1 chip might have problems with booting files. To surpass this hitch, allow booting from an external media before you downgrade.
  2. Reinstalling macOS Big Sur from Recovery Mode. Now that you have entered Recovery Mode on your Mac, it is time to reinstall the OS of the computer. From the Utilities screen of the macOS Recovery, select the Reinstall option and click on Continue. Follow the on-screen instructions and steps – they will guide you through the whole process.

Toolkit for safe macOS downgrade

After months of waiting, macOS Big Sur was released in November 2020. No matter how great macOS Big Sur is, you can experience performance issues as you update your Mac. The good thing is you can downgrade to the previous macOS version. There are two ways to revert from Big Sur to Catalina. The first one involves restoring a Time Machine backup. MacOS Catalina is slightly outdated since the release of macOS Big Sur in November of 2020. Nevertheless, many users prefer to stick with it because it's much more familiar visually. And it offers a bunch of expanded features, such as a screen extension with an iPad or the new Apple Podcasts app.

Easily switch between macOS versions with Setapp. Get access to the apps that will keep your Mac invincible and your data protected.

Before you make a decision to uninstall Big Sur, check out some common macOS 11 problems and fixes. Maybe, the problem that is hampering your flow is on the list — and you can easily solve it. Also, if your Mac runs macOS Big Sur beta, you should know the public version available starting November 12 fixes most of the problems.

If you go like 'All right, thanks, just tell me how do I uninstall Big Sur from my Mac' — fair enough. The good news is it's easy to roll back macOS update. Follow the guide below.

How to downgrade from Big Sur step by step

Just to clarify the process a little bit, a downgrade from Big Sur covers five important steps — from backing up all the files you've acquired since upgrading, to restoring those on macOS Catalina. There are a few tools you'll need to use to downgrade safely: Primarily, a backup utility (Apple's native Time Machine or a more advanced third-party app like Get Backup Pro) and CleanMyMac X for keeping things tidy. Now when you're all set, let's get into it.

Best backup app for Mac

Before you roll back to the old macOS, create a secure backup of all your data with Get Backup Pro. So that there’s nothing to lose.

1. Backup your data (pretty please)

Even if you've just recently upgraded and haven’t managed to accumulate lots of data on macOS Big Sur, don’t skip this step. Downgrading means you erase everything from your hard drive. So whatever you’ve been working on since installing macOS 11 will be gone. Make sure you avoid the trouble and create a quick backup. You can do this with Time Machine, but we recommend Get Backup Pro for creating a bootable backup. This will give you an exact copy of your drive, with all saved settings — so that you can pick up where you left off.

Here’s how to back up data before you uninstall Big Sur:

  1. Open Get Backup Pro from Setapp

  2. Hit the plus button at the bottom to create a new backup

  3. Name your backup project

  4. Pick a backup destination and customize settings if necessary

  5. Choose files, folders, and apps data you want to add to the backup

  6. Hit Start.

It’s a good idea to use CleanMyMac X for a system cleanup before you create a backup. This way, you’ll avoid backing up unneeded files and duplicates, and therefore run a smooth and quick backup process. Plus, the app is generally a good tool to keep at your fingertips to remove any clutter. Believe me, your Mac has a lot of it. Here’s how CleanMyMac X works:

  1. Open the app and hit Scan

  2. Wait for CleanMyMac X to finish the scanning process

  3. Hit Run if you want to remove all the junk, or Review if you want to select the files that should be deleted manually

  4. That’s it! You’re all set for a clean backup.

2. Install macOS Catalina on a bootable drive

It might seem a bit counterintuitive, but you have to install macOS Catalina on an external drive before you erase Big Sur. This requires some Terminal work, which we’ll guide you through in a minute. Before that, make sure your Mac can boot from external media.

Allow booting from external media on new Macs

If you own a MacBook Air, MacBook Pro, or Mac mini with the T2 security chip (2018 models and newer), you might experience problems with booting files. To avoid this, you should allow booting from external media before you run downgrade to Catalina:

  1. Restart your computer and boot in Recovery Mode (hold down Command + R once the Apple logo appears)

  2. Access Utilities > Startup Security Utility

  3. Enter your firmware password (note that this is the password you used to enable Startup Security Utility and it’s different from your admin and Apple ID credentials)

  4. In External Boot, check the box next to “Allow booting from external media.”

Once you’re all set, it’s time to get Catalina back. First, download macOS Catalina from the Mac App Store, the usual way. While installers of the latest macOS versions are available only before the official release of the new one, you should do this as early as possible.

Then, install macOS Catalina on 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 minimum 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 your drive (make sure you name it if you have more than one)

  6. Select APFS or macOS Extended format > Erase.

Install macOS Catalina on a formatted drive:

How To Update Macos Big Sur

  1. Open Finder > Applications

  2. Launch Terminal from Utilities

  3. Type the following command

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

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

  1. Click Enter/Return

  2. Confirm your action by entering the admin password > Y

  3. Click Return

  4. Once Terminal says “Done,” you can quit it and eject the hard drive.

3. Remove macOS 11 from hard drive

Now is the time for goodbye. Here’s how to downgrade from 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. Hold down Command + R to reboot in Recovery mode

  3. Open Disk Utility > Continue

  4. Select your Startup Disk > Erase

  5. Select APFS or macOS Extended format and confirm your action.

4. Reinstall macOS Catalina on your Mac

Next thing, run a downgrade to Catalina by reinstalling it on 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. While your Mac restarts, hold down Option

  5. Once the list of startup disk options appears, select the bootable drive with macOS Catalina installer

  6. Hit Continue, agree to the licensing terms, and wait for macOS Catalina to reinstall.

5. Restore data from backup

The last step is to bring back all the data you’ve compiled since upgrading to Big Sur. Again, a backup is essential since it will help restore both your files and saved settings. You can restore everything with the same tool you’ve used previously to create a backup.

Here’s how to restore a Time Machine backup:

  1. With your Mac connected to the internet, restart the system

  2. Hold down Command + R to enter Recovery

  3. Access Utilities > Restore from Time Machine Backup > Continue

  4. Select the backup source > Continue

  5. Select your backup > Continue

  6. After Time Machine restores data from the backup, your Mac will reboot.

If you used Get Backup Pro for your backup, restoring data is even easier. All you have to do is launch the app, select your backup from the list, and hit Restore. Select a custom location for your files and once again click on the Restore button. That’s it. All your data and settings will be back on macOS Catalina in a minute.

That’s about it. Whenever you’re wondering how to go back to previous macOS, you can use the guide described above. All the instructions are pretty universal, except you should adjust the Terminal command when installing old macOS on a bootable drive.

In case your Mac is slowing down or else behaving strangely after the downgrade, we recommend to get iStat Menus for advanced system performance monitoring. This app will help you understand the source of the problem — whether it’s login items, network problems, or disk activity — and fix them accordingly.

iStat Menus is available on Setapp, along with the useful utilities like CleanMyMac X and Get Backup Pro. So you can use it all from one place for 7 days free. Hopefully, this toolkit will help you with how to downgrade macOS Big Sur, as well as keep your Mac in perfect shape, anytime.

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From Jun 2020 to Aug 2020, Apple has released several beta versions for macOS 11 Big Sur, both developers and testers can install and run it on a supported Mac. You may be one of them, starting to use this new macOS but unfortunately run into some issues and want to revert to previous Catalina or Mojave version.

No worries, here we will list the easy steps to downgrade macOS Big Sur to Catalina without losing data.

Recover Data After Mac Downgrade

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  • Support file recovery on 200+ formats: video, audio, photo, docs, etc.
  • Preview files before recovery
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Why We Need to Downgrade Big Sur to Catalina?

MacOS 11 Big Sur is absolutely the biggest update these years since it has moved from 10 to 11, you can find a bunch of update as following in Big Sur:

  • New design
  • Intuitively customized Safari browser
  • Updated Messages app (better control of conversation)
  • Redesigned Maps for better and easier navigation
  • Improved transparency for Mac App Store downloads
  • Expanded photo editing features
  • Faster updates to the latest version

……

All the revealed new updates added to macOS11 Big Sur stimulate mac users to upgrade and take the first bite on this macOS version. But later, there occurs problems and some of them want to revert to the previous Catalina version for one or another reasons:

  • The Beta version is not perfect, you want to download the official version later;
  • It takes longer time to get used to the new version and you don’t want to waste time;
  • MacOS 11 Big Sur keeps causing problems;
  • Your hardware is not highly compatible on this new version (compromised audio, video or image quality);
  • Your favorite app doesn’t work on the new version;

……

No matter what your reason is to revert to an older version, you can refer to following part to downgrade from Big Sur to Catalina without losing data.

How to Downgrade Big Sur to Catalina without Losing Data?

To downgrade Big Sur to Catalina without losing data, here are 6 steps to follow. Before the downgrade, your data matters the most, so don’t forget to back them up though it takes time to finish a backup.

Step 1. Prepare your Mac for downgrade

You should quit running programs and leave enough space (15GB to 20GB) to install Catalina after erasing Big Sur from your Mac hard drive. Also, make sure your mac is connected to the internet for later macOS installer download.

Step 2. Backup files (Important and Required)

It is safe to upgrade or downgrade a macOS version, there is no harm done to your files or data, but data loss after mac update or reversion happens sometimes. If you don’t want to render your data under any potential risks, you are highly recommended to back up files.

There are 2 ways to back up file, either back up your files to an external hard drive with Time Machine or upload your data to cloud-based service for storing, like iCloud, DropBox, OneDrive. But here Time Machine backup is recommended.

  1. Connect an external hard drive for backup to your mac;
  2. Run Time Machine and set it up for backup;
  3. Click on the Time Machine icon in menu bar, choose Back up Now;
  4. Wait for the backup to finish.

Step 3. Erase macOS 11 Big Sur from your Mac

  1. Click Apple icon and go to Restart;
  2. Hold down Command+R when rebooting to reboot your mac in Recovery Mode;
  3. In the pop-up interface, choose Disk Utility>Continue;
  4. Then select your Startup Disk, click on Erase tab;
  5. Choose APFS or macOS Extended format and confirm to Erase.

Step 4. Install macOS Catalina or Mojave

There are 3 methods to install older macOS version on your mac.

Method 1. Download from Mac App Store and Install

  1. Launch Mac App Store;
  2. Search macOS Catalina or Mojave, click Download;
  3. When the download finishes, follow the on-screen instructions to install macOS Catalina or Mojave;

Method 2. Reinstall macOS Catalina or Mojave from Internet

  1. Click on Apple logo>Restart;
  2. Hold down Command+R when rebooting your mac;
  3. In the pop-op macOS Utilities interface, choose Reinstall macOS>Continue;
  4. Agree to the terms and follow the instructions to download and install.

Method 3. Reinstall macOS Catalina or Mojave from Bootable Drive

  1. Create a bootable drive of macOS Catalina or Mojave
  2. Connect the bootable drive to your mac;
  3. Click on Apple logo>Restart;
  4. Hold down Option when rebooting your mac;
  5. Choose the bootable drive with macOS Catalina or Mojave installer;
  6. Click on Continue, agree to the terms and install a previous macOS version onto your mac.

Step 5. Restore Backup with Time Machine

The only change you want for the downgrade is turning back to a previous macOS version, but you want the files and settings the same as before. In this case, you should restore both your files and settings from a Time Machine backup.

  1. Click on Apple Logo>Restart;
  2. Hold down Command+R during mac rebooting;
  3. Choose Restore from Time Machine Backup from the macOS Utilities interface and click on Continue button.
  4. Choose the Time Machine backup disk>Continue;
  5. Select the latest backup, click Restore>Continue.
Downgrade

Step 6. Check if everything is back now!

Now, run your apps on macOS Catalina and check if everything goes well.

Update

If the downgrade still causes problems, restart your mac or reinstall Catalina/Mojave to fix it.

What If Data Lost/Deleted after macOS Big Sur Downgrade?

But what if we still got data lost or deleted after macOS Big Sur downgrade to Catalina or Mojave? You can recover them back with Time Machine backup by following the tutorial in above Step 5. If this still cannot get back your files, you need a professional data recovery program---Cisdem Data Recovery.

Cisdem Data Recovery is a program to recover lost, missing, deleted, formatted files from both internal and external hard drive on mac. It applies to data loss due to system crash, update or downgrade, also supports file systems like APFS, HFS+, FAT16, FAT32, exFAT, NTFS, etc.

Main Features of Cisdem Data Recovery

  • Recover lost, deleted, formatted data;
  • 5 recovery modes enable users to recover files lost under different situation;
  • Recover files from internal and external hard drive (USB, SD Card, Media Player)
  • Support file recovery on 200+ formats: video, audio, photo, docs, etc.;
  • Support various file systems: APFS, NTFS, HFS, FAT, etc.;
  • Preview files before recovery;
  • High recovery rate;

How to Recover Data After macOS Downgrade from Big Sur to Catalina?

How To Reinstall Catalina From Big Sur

  1. Download and install Cisdem Data Recovery to your Mac;
    Free Download
  2. Choose a data recovery mode basing on your need. Basic mode runs a quick scan, while Advanced mode runs a deep scan;
  3. Select the location where you lost the files and click Scan;
  4. Preview the found files; All the founded files will be categorized in different folders, check the file and preview before recovery;
  5. Select the found file and recover them onto your mac. Check the box before found files, stop the scanning process if you want to recover before the end of a scanning process. Click Recover to get all lost files after macOS Big Sur downgrade back to your mac.

Conclusion

No matter you want to downgrade from Big Sur to Catalina or Mojave without losing data, or just want to upgrade from an earlier version to the latest macOS, the backup process is mandatory in case of any data loss. If a data loss happens and you don’t have a backup, you will need a dedicated program like Cisdem Data Recovery to do the job.