Reinstall Catalina From Big Sur

  • Now you are ready to downgrade from macOS Big Sur to Catalina. As we mentioned above, you can restore the earlier macOS from the backup or reinstall it using a bootable installer. If you use Time Machine, follow these steps to reinstall macOS Catalina: Connect the external drive with a backup to your Mac. Restart your Mac in Recovery Mode.
  • Follow the on-screen instructions to reinstall macOS Catalina. Downgrade macOS Big Sur with a macOS Catalina bootable installer. If you have some trouble with the above two ways, you can try to downgrade macOS Big Sur via creating a macOS Catalina bootable installer.

The key to reinstall mac OS Big Sur, Catalina or Mojave without losing data is the backup, since no one can guarantee all data will be perfectly maintained after macOS reinstallation. However, if we unfortunately lost files after macOS reinstallation, Time Machine or Cisdem Data Recovery is helpful to recover them back.

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

  • Recover files lost due to macOS update, downgrade, crash, etc.
  • Recover lost, deleted, formatted data
  • 5 recovery modes: Basic, Advanced, Formatted Drive, Trash, Extenal Devices
  • Recover files from internal and external hard drive (USB, SD Card, Media Player)
  • Support file recovery on 200+ formats: video, audio, photo, docs, etc.
  • Preview files before recovery
Free Download

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.
How do i reinstall os x catalina from big surReinstall Catalina From Big Sur

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.

Step 6. Check if everything is back now!

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

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?

  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.

New things are always exciting and they definitely give us an adrenaline rush trying them. Somehow, not all new things are a perfect fit for us. This might be the case with macOS 11 Big Sur. You definitely switched from your previous MacOS Catalina to the new enhanced MacOS 11 Big Sur and after your high, you realized that you were perfectly comfortable with MacOS Catalina. It’s not too late, you can still seamlessly downgrade to Catalina without losing any of your data.

Here is how you can downgrade seamlessly in 5 simple steps;

First backup your data

You will need to back up your accumulated data since the upgrade. You might have used the MacOS 11 Big Sur for a short while but this step is important nevertheless and this is something very important when you are doing downgrade from big sur to catalina.

To do this you may first need to clean your system so you can retain only important files. CleanMyMac X can help you accomplish this by getting rid of unseen junk and clearing your accumulated clutter and this is something very important and should be done well. There are many people who are not sure about how it is done and regret it later and you should try and avoid being there and so be careful once you are doing the downgrade from big sur to Catalina.

Once done, you can now backup your cleaned data using the Time machine tool or an external backup tool like getting Backup Pro.

Time Machine backup.

Reinstall Catalina From Big Sur

  1. Backup your data by opening the system preferences and select Back up and this is something very important and you should never ignore it and if you do that then there could be an issue and that is the last thing that you want. Things need to be done in the right way to avoid any kind of issue and you will not have an issue.
  2. Select the drive for use and you are good to go.

Install macOS Catalina on an external drive

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. This is something important and you should look for doing it the correct way and once you do that then there will be no problem at all for anyone which is something very important and should not be ignored at all and one has to take things into consideration in the right way which is something very important and should not be looked anywhere else which is something very important.

Once you have booted your Mac externally, you can get back Catalina by simply downloading it from the App store. Thereafter, install macOS Catalina on a formatted external drive and should be done in the right way for a good result.

Erase macOS Big Sur

You have finally downloaded Catalina? Now it’s time to get back to your comfortable MacOS and say bye to Big Sur. Erase macOS Big Sur from your hard drive.

Reinstall macOS Catalina on your Mac

You can now run a downgrade to Catalina by reinstalling it on Mac. For this to happen you need to ensure you are connected to the internet.

  1. Insert your bootable external drive into your Mac then select restart on the menu.
  2. Hold down options while your Mac restarts, a list of startup disks will appear, choose the bootable drive with macOS Catalina and select continue.
  3. Finally, agree to the licensing T & Cs then wait for Catalina to reinstall

Restore data

The final step is to restore the data that you had backed up. Depending on what you had used, this is how you restore your data:

Time Machine Backup

  1. Restart your Mac then hold down Command + R to initiate recovery.
  2. Access utilities then restore from Time Machine Backup and continue.
  3. Select the backup source then proceed to back up and wait for your data to be restored.

After data restoration, your Mac will reboot.

How To Reinstall Catalina From Big Sur

For Get Backup Pro, you just have to launch the app then select backup and restore your data to a location of your choice. All your data will be restored on MacOS Catalina and you are all set with a smooth downgrade on your sleeve.