Reinstall Catalina From Big Sur

If you have installed Big Sur, Catalina, Mojave or earlier versions, you may have to reinstall macOS for following reasons:

  • Reinstall When There is New macOS Version Available

Apple keeps working constantly to fix bugs, make performance tweaks, add new features or enhance coding. Therefore, doubtless, there will be new versions of macOS available to upgrade and reinstall.

How Do I Reinstall Os X Catalina From Big Sur

Reinstall macOS Catalina on Your Mac. Restore Time Machine Backup (Optional) Step 1. Back up your Mac (Very Important) If you want to downgrade from Big Sur to Catalina without losing data, it is important to save and backup your data on the macOS Big Sur, so you do not lose any important files.

  • Your Mac is Running Slow

As we all know, for no specific reason, system reinstallation can magically solve a slow Mac in most cases.

  • Your System Keeps Crashing or Works Improperly
  • 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.
  • To reinstall macOS in macOS Recovery mode: Step 1: Make sure your Mac is connected to a stable Internet within all the following steps. Step 2: Identify it's an Intel or M1 Mac, and immediately do one of the followings. Press and hold Command + Option + R.This allows you to reinstall the latest version of macOS that is compatible with your Mac.

When you continuously see error messages appear on your mac, or your programs randomly crash/freeze for no reason, like FaceTime won't work, Contacts or Calendar shows a delay or mess, blue teeth or WiFi won't connect…Then, you have a good reason to reinstall macOS.

  • You are Going to Sell the Mac

In the case that you want to sell your mac, besides erasing all your personal data and traces on the mac, you will need to reinstall macOS as well.

How To Downgrade Big Sur To Catalina

It is not complicate to reinstall macOS Big Sur or Catalina, but if you want to reinstall macOS without losing data, there are 3 steps you must follow.

Recover Files after macOS Reinstall

  • Recover data lost due to macOS reinstallation, upgrade, downgrade
  • Recover data lost due to accident deletion, formatting, etc.
  • Restore data from both internal and external storage device
  • Recover videos, audios, images, documents, and other 200+ files
  • 5 recovery modes to find files back easily
  • High recovery rate
  • Support Big Sur, Catalina, Mojave and earlier
Free Download

3 Steps to Reinstall macOS Big Sur or Catalina without Losing Data

We all save tons of data on our Mac, so when we decide to reinstall macOS Big Sur/Catalina, the top concern always goes to “will I lost everything if I reinstall macOS”. In fact, reinstallation of macOS doesn’t necessarily cause lost data, it just create a new copy, your existing files and data saved in programs won't be altered or deleted. But just in case of bad luck, we need to do some work on BACKUP, this is crucial for macOS reinstallation without losing data.

Step 1. Prepare Your Mac for Reinstallation.

  • Make enough room for Big Sur or Catalina reinstallation, at least 36GB, so the reinstallation process won't pause or stopped for insufficient space.
  • Also, quit all apps or programs under work, so your Mac is fully geared to reinstall.
  • Check drive conditions. Open Disk Utility and perform the Frist Aid on your hard drive where to reinstall the macOS to make sure your drive is in good condition for reinstallation.

Step 2. Backup All Your Files for macOS Install (Crucial)

Backup is an indispensable step involved in the macOS reinstallation, here are several options to backup your data.

Option One: Using Time Machine

  1. Go to Finder>Application, launch Time Machine and choose “Set Up Time Machine”.
  2. Click “Select Backup Disk” to choose an external hard drive to back up the files.
  3. Then Check the box before “Back Up Automatically”. Also, you can adjust the backup setting in menu “Options”.

If this is the first time you use Time Machine to backup, wait patiently for Time Machine to complete the backup, it will prompt the notification once finishes.

Option Two: Using Hard Drive

  1. Connect your hard drive to Mac.
  2. Open Finder to check if your hard drive is present under “Devices”.
  3. Create a new folder, copy and paste or directly move the items you want to save from Mac to this folder.
  4. Finally, eject your hard drive.

Option Three: Using iCloud Service (Backup Desk and Documents Folders)

  1. Go to Finder>System Preference, click on “iCloud” to bring up its main interface.
  2. Click the “Options” button for “iCloud”, and check the box before “Desktop and Documents Folders”, then click on “Done”.

Most of our mac users prefer to backup all files but apps. So, to save you from troubles of lost data due to macOS reinstallation, you are recommended to keep records of what apps you have installed, the account and password, also, you can take screenshots of the settings.

Step 3. Reinstall macOS Big Sur or Catalina without Losing Data.

Option #1: Reinstall macOS without Losing Data From Internet Recovery

  1. Click the Apple icon>Restart.
  2. Hold down the key combination: Command+R, you will see the Apple logo.
  3. Then choose “Reinstall macOS Big Sur” from utilities window and click “Continue”.
  4. Select your hard drive, click “Install” and wait for end of reinstallation.

Option #2 Reinstall macOS without Losing Data From USB

  1. Download the macOS Big Sur install from Mac App Store onto your Mac;
  2. Then connect the USB flash drive to your Mac;
  3. Open Disk Utility program on your Mac, choose the USB flash drive and click Erase to have a clean drive for the reinstallation;
  4. Open Terminal, copy and paste sudo /Applications/Install macOS Big Sur.app/Contents/Resources/createinstallmedia;
  5. Then add the volume of usb flash drive: --volume /Volumes/MyVolume, replace MyVolume with your usb flash drive name, mine is Untitled;
  6. Press Enter, input password and wait for the process to finish;
  7. Quit Terminal, restart your Mac, hold Command+R when starting Mac until you see the apple logo;
  8. Login into your Mac with password, go to the menu bar>Utilities>Startup Security Utility, enter password again;
  9. Choose Medium Security under Secure Boot and allow booting from external media;
  10. Restart your Mac, in the same time, hold the Option key;
  11. Choose Install macOS Big Sur, click Next and input password, choose Install macOS, continue to finish mac reinstallation from usb.

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What if You Lost Data After macOS Big Sur Reinstallation?

However, losing data after reinstallation still happens. It may result from a interrupted installation (power-off/poor internet connection), corrupt setup, insufficient space or improper actions. Then, what to do if you lost data after reinstallation? Here are 2 methods.

Method 1: Use Cisdem Data Recovery to Recover Data

In the case you didn’t do backup before reinstallation, you will need a dedication data recovery program to find the lost data for you.

Here we recommend Cisdem Data Recovery, a powerful mac program allowing users to recover lost/deleted/corrupted/formatted files from a wide range of external or internal storage devices, no matter the file is lost due to human errors, power-off, reinstallation, upgrade, virus attack or disk crash.

Main Features of Cisdem Data Recovery

  • Recover files lost due to OS reinstallation, upgrade, downgrade;
  • Recover deleted, formatted and lost files;
  • Restore files from internal and external hard drive, USB, SD Card, flash drive, etc.;
  • Restore videos, audios, images, documents, archives, 200+ types;
  • 5 recovery modes: Basic, External Drive, Formatted Drive, Trash, Advanced;
  • Preview files before recovery;
  • Fast scanning and recovery;

Steps to Recover Lost Data after MacOS Reinstallation

  1. Download and install Cisdem Data Recovery on Mac.
    Free Download
  2. Choose a Recovery Mode according to your need.
    If you want an efficient recovery, choose “Basic Data Recovery”, if you want to recover files with a higher success rate, try “Advanced Data Recovery”.
  3. Select the hard drive where you originally stored the files on mac. Then click “Scan”.
  4. Check and preview files found by Cisdem Data Recovery.
  5. Select files to recover.
    Check the box before files that you want to recover, then click “Recover” to find back the lost data caused by reinstallation.

Method 2: Use Time Machine to Recover Data with Backup

If you have backed up your files on mac, you can use Time Machine to restore the lost data.

  • Step1. Go to Finder>Applications>Time Machine, launch it and choose “Enter Time Machine”.
  • Step2. In the popped-up window, use the arrows and timeline to browse the local snapshots and backups.
  • Step3. Find the deleted files, then click “Restore” to recover the lost data caused by reinstallation.

Conclusion

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.

So, do you have any other tips to reinstall macOS without losing data? Please share with more of our mac users.

The MacOS Big Sur upgrade, while filled with enhancements, is not without its difficulties: Users have encountered a range of bugs, consisting of issues that temporarily bricked their Macs, video porting issues, unexpected slowdowns, and more. Some users have preferred to return to MacOS Catalina totally, and wait till all the major bugs with Big Sur have been dealt with.

If that explains you, there is a way to roll back Big Sur and go back to the more pleasant Catalina OS, although it does take the right procedure. Here’s what you require to do.

Action 1: Back up your data

If you haven’t currently done so, now is the time to back up your information. You can always utilize Time Maker to back up data on a Mac, but buggy os can make Time Machine tough to use, so it’s wise to

find a backup approach that doesn’t rely on MacOS. An external hard drive can be found in extremely beneficial here. If you have great deals of iCloud area, you can likewise keep all important files in iCloud for simple retrieval if needed. Oh, and if you’re on a MacBook, this is also a good time to plug your Mac into a power source and established where you can remain for a while.

Action 2: Close down and go into Healing mode

Close all your apps, and finish a complete shutdown for your Mac. You can either push the physical power button or select the upper-left Apple icon and pick Shut Down to start. Your Mac may take a while to completely turn off. If a bug turns up and freezes your Mac during this procedure, hold down the power button for a number of seconds to force a shutdown.

When your Mac is off, disconnect any devices except for your mouse and keyboard. Then press the power button to turn it back on. When your Mac is powering up, immediately press and hold the Command and R keys, up until you see the Apple logo appear. Now release those keys, and your Mac needs to go into Recovery mode. You will know this worked if you see the window called MacOS Utilities appear.

Keep in mind: If you have a Mac with an Apple silicon chip, pushing and holding the power button should take you to a start-up menu, where you ought to choose Options rather.

Action 3: Try To Find a Time Machine backup

< img src=' image/gif; base64, R0lGODlhAQABAIAAAAAAAP /// yH5BAEAAAAALAAAAAABAAEAAAIBRAA7″alt =””/ > Examine MacOS Utilities. The very first choice ought to be to Bring Back from Time Machine Backup. Start by picking this option, then choosing Continue, and your Mac

will search for at any time Machine copies of your OS. Here’s where things get a little difficult: If you understand you have a Time Maker copy and it is stored on an external disk drive, you need to plug in that external drive before selecting this alternative. If you aren’t sure if you set Time Device to make regular copies, let your Mac search and see what it discovers.

How To Reinstall Catalina From Big Sur

If your Mac does return a Time Maker backup, take a look at what operating system it is and the date of its creation. You will desire a Time Device backup from right before you set up Huge Sur. If a copy appears like what you need, pick it, and pick a destination disk where the backup will be stored. Then choose Bring back, and choose Continue when prompted. You might be asked to choose classifications of information to restore– if so, merely pick all of them.

Step 4: Use the Reinstall MacOS alternative as an alternative

If you have not been utilizing Time Device and do not have any backups, there’s still another alternative you can attempt. Back out to MacOS Utilities, and this time pick the Reinstall MacOS choice. Select Continue, and enter your Apple ID. Your Mac will then search for a web connection, which is required for the reinstall process. If your Mac is having problem linking to Wi-Fi, you might require to run an Ethernet cable television from your router to your Mac for a wired connection.

Essential note: This process is effective if Huge Sur is having problem booting up after a buggy installation. If Big Sur is already set up and you have actually been using it, it might just get reinstalled again– which isn’t what we desire. There are ways around this!

How do i reinstall catalina from big sur

How To Update Macos Big Sur

  • First, attempt starting up in Healing mode once again, this time utilizing the Alt + Command + R secrets. This should make sure the Reinstall alternative is set to the variation of MacOS that your Mac came with. If you have a Mac that is only a years of age or so, this ought to be MacOS Catalina, which fixes your problem.
  • If your only option is to re-install Big Sur, you will require to produce a bootable installer with MacOS Catalina instead, and utilize it as a start-up disk. Apple has particular directions for this procedure, which is not complicated however will need a 12GB flash drive to work.

When your Mac begins reinstalling MacOS Catalina, it’s going to take an hour or two to complete, so stay patient. Fortunately is that your files and apps– unless corrupted– must be conserved and ready after your Mac is done.

Step 5: Remove your Start-up Disk if essential

If you have actually attempted everything but your Mac is still experiencing serious breakdowns that make it unusable, you ought to try erasing the startup disk entirely. Pick Disk Energy at the MacOS Utilities menu, choose Continue, and after that pick your Startup Disk from the menu options. Not sure which disk it is? If your Mac is still functional, you can go to System Choice and select Startup Disk to have a look.

Now select Erase. Your Mac will let you pick which format you wish to utilize– select APFS. If inquired about partitioning, select GUID Partition Map. Verify the process, and the startup drive will be erased, enabling a cleaner MacOS Catalina set up. Since lots of Mac setups use an additional disk for storing individual files, these might largely remain intact.

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