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Reinstall Macos Catalina From Big Sur

Reinstalling the OS of your Mac is sometimes required as a last resort option when troubleshooting a certain software problem. If none of the other fixing methods have worked out so far, this final fixing method should be enough to bring things back to normal and restore your Mac to its regular state.

Installing MacOS Catalina from Big Sur You’re now watching this thread and will receive emails when there’s activity. Click again to stop watching or visit your profile/homepage to manage your watched threads. Big Sur is a big mess and a big fail! My sister downloaded it and her late 2015 iMac became useless. I tried to reinstall it and it hung up at the dreaded 'Less than one minute remaining' Now I have to do a clean erase and load Catalina. Reminds me of all the bad OS from Microsoft in the early days. The MacOS Big Sur update, while filled with improvements, is not without its difficulties: Users have come across a variety of bugs, including problems that temporarily bricked their Macs, video. 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.

However, before you continue with the macOS reinstallation, we advise you to make sure that you have indeed exhausted all other options and made sure that this really is the only thing that you haven’t tried so far. If that is your case and you are sure you wish to continue, here is a guide that can help you with the reinstallation process.

Accessing macOS Big Sur Recovery

MacOS Recovery is a special mode that gives you access to different system repair tools that can help you deal with different issues that your Mac has. In the macOS Recovery Mode, you can use the Time Machine backup tool, get online help for your problem, erase the hard drive of your Mac, reinstall your macOS, and more.

Entering Recovery Mode is a bit different depending on whether your Mac has an Apple Silicon or an Intel processor. To find out the type of processor that your Mac has, click on the Apple Menu, select About this Mac, and look at the information in the window that opens. If you see an entry labeled Chip with the model of the chip written after it, this means that your Mac is with an Apple Silicon processor. If instead of that there is a “Processor” entry followed by the specific processor model, it means that your Mac is equipped with an Intel processor. Depending on which one of the these two your Mac has, do either of the following:

  • Macs with Apple Silicon processors: With the computer turned off, press and hold down the Power Button, wait for the Startup Options screen to get displayed on your screen, and then release the button. Now select the Options icon and click on Continue.
  • Macs with Intel processors: Make sure that your Mac is connected to the Internet and turn it off. Then start the computer and immediately after that hold down the Command ⌘ + R keys from the keyboard. Keep holding them until the Apple logo (or another image) gets displayed on the screen.

If your Mac requires you to log in to any of your Mac accounts, select an account you know the password for and that has Admin privileges.

Macos

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.

  1. From the Utilities screen of the macOS Recovery, select the Reinstall option and click on Continue.
  2. Follow the on-screen instructions and steps – they will guide you through the whole process.
  3. Be sure to adhere to the following tips while in the process of reinstalling macOS.
    • Do not put your Mac to sleep or close its lid while the reinstallation process is underway. While macOS is being reinstalled, your Mac may restart several times and the screen may go black and stay that way for several minutes – even if this happens, stay patient and wait for the process to complete. Until macOS gets reinstalled, do not close, put to sleep, or turn off your MacBook!
    • If you are asked to unlock the disk of your Mac, do so by filling in the password that you use to log in to your main Mac account.
    • If the macOS installer cannot find your disks or it tells you that the installation cannot be completed on the specified disk, you may first need to erase that disk and try again.
    • If you are given the choice between installing Macintosh HD or Macintosh HD Data, pick the first option.

Once the installation of macOS is complete, you will be asked to set up the preferences of the computer. Complete the set up according to your personal preferences and you will be good to go.

If you have reinstalled the OS because you intend to sell or give away your Mac and want to allow its new owner to set it up themselves, press Command-Q to close the Setup Assistant and leave the setting-up process to the future owner of the computer. After that, click on the Shut Down button to turn off the Mac.

Additional options and tips for installing/reinstalling macOS

The default setting of macOS Recovery is that it will install the latest version of the operating system that was previously installed on the computer. If you want, you can get it to install a different version of the OS by using one of the following options:

  • On a Mac with an Intel processing unit, you can press down and hold the Option + Command + R keyboard combination (instead of the Command ⌘ + R combination) as soon as you turn on the computer. This will cause macOS Recovery to install the latest stable macOS version that is compatible with the machine. There are two exceptions here:
    • If macOS Sierra 10.12.4 or another later version of macOS has never before been installed on the computer, the macOS version that will get installed will be the one that originally came with the machine, or another macOS version that is closest to the original one.
    • If the computer is equipped with the Apple T2 Security Chip and a macOS update has never before been installed on the machine, macOS Recovery will install the latest version of the OS that was installed on the computer.
  • If your Mac previously had the macOS Sierra 10.12.4 version of the OS or a later version, you can also use the Shift + Option + Command + R combination once you start the computer (press and hold the mentioned buttons) instead of the two previous combinations to make macOS Recovery install the OS version that was originally on your Mac when you bought it or the closest other OS version that is still available.
  • To install a different macOS version that macOS Recovery doesn’t allow you to install, you can instead go to the App Store and install the desired OS version from there.
  • Another way to reinstall your macOS is to create a bootable USB drive and install the desired OS version from it.
  • If the logic board of your Mac has just been replaced after your machine has been repaired by a technician, it is likely that macOS Recovery will only offer you to install the latest OS version that is compatible with the computer.
  • If the entire disk of your Mac has just been erased (instead of only the startup volume), macOS Recovery will probably only allow you to install the version of the OS that came with the computer when you first bought it (or the closest other available macOS version).

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.
The problem is that it might not always work as intended. Glitches in macOS Catalina are commonplace: in fact, all existing operating systems like Mojave or High Sierra could freeze and crash from time to time. No software is immune.

But what do you do in this case? The surefire way to deal with jaded performance is to reinstall macOS Catalina altogether. Read through our guide below to learn how.

How To Reinstall Mac OS Catalina

It’s important to note that when you reinstall macOS Catalina the process simply updates the operating system and doesn’t affect any files on your hard drive or user files or even settings. That makes reinstalling principally different from performing a clean install, which erases everything.

Here are the proper steps to follow to reinstall mac OS Catalina.

1. Back up your Mac first

By default, the best thing you could do before making any significant changes to how your Mac works is to back it up. Backups are just like saves before encountering challenges in video games — represent the point you can always come back to.

Reinstall Macos Catalina From Big Sur

There are lots of great backup solutions on the market to suit every need. If you don’t have the time to search for something specific, your Mac features a decent native option — Time Machine.

To get Time Machine started:

Reinstall Macos Catalina From Big Sur Windows 10

  1. Connect an external USB or WiFi hard drive to your Mac
  2. Go System Preferences ➙ Time Machine
  3. Click on Select Backup Disk…
  4. Press Use Disk

2. Delete junk off your Mac to speed it up

Reinstall Macos Catalina From Big Sur Free

There’s nothing better than the feeling of a brand new Mac with a brand new macOS. If only the latter is new, the experience could be subpar. Trying to get the most out of macOS Catalina on your older machine might be a challenge. But don’t hurry to your local Apple Store just yet — not all is lost.

Just like the dust behind your couch or on the top of your kitchen cupboards, small bits of system files, caches, and hidden libraries tend to aggregate over the years and never get deleted, eventually slowing down everyday processes. While it’s possible to clear out some of them manually, others require specific technical knowledge and lots of time.

Luckily, there’s a professional automatic solution available — CleanMyMac X. Optimizing behind-the-curtain processes on your Mac with CleanMyMac X is no more difficult than clicking a single button:

  1. Download a free version of CleanMyMac X.
  2. Open the app and navigate to System Junk in the left-side panel.
  3. Click Scan and wait for the process to complete.
  4. When done, press Review Details.
  5. Uncheck anything you’d like to keep and click Clean.

Now your Mac is free of all the pointless log files, user caches, language files, old updates, and more. Which directly translates into improved processing power, memory usage, and response time. At last, your Mac is ready to take full advantage of macOS Catalina.

3. Reinstall macOS Catalina in Recovery Mode

How To Update To Macos Big Sur

How do i reinstall os x catalina from big sur

With your Mac in top shape, it’s time to get that macOS Catalina download link. Surprisingly, you won’t find it in Software Update or even App Store (where it used to be in macOS High Sierra).

The correct way to reinstall macOS Catalina is to use your Mac’s Recovery Mode:

  1. Restart your Mac and then hold down ⌘ + R to activate Recovery Mode.
  2. In the first window, select Reinstall macOS ➙ Continue.
  3. Agree to the Terms & Conditions.
  4. Select the hard drive you’d like to reinstall mac OS Catalina to and click Install.

Automatically update all your software for Catalina

The reinstallation process will start shortly and roughly take 30 minutes. When complete, your Mac will start up as usual. No files should be lost, but it’s always a good idea to check CleanMyMac X’s Applications Updater to see if you can improve compatibility of the new macOS with any of your existing apps:

  1. Launch CleanMyMac X.
  2. In the left-side panel, navigate to Updater.
  3. View any available updates and their notes and click on Update.

Reinstall Macos Catalina After Big Sur

This Updater tool in CleanMyMac X automatically searches for latest available versions of ALL your apps. One or two clicks and everything feels fresh. It even updates the macOS file itself.

Trust in your backup

Finally, in case you notice any files or apps missing, or settings misconfigured, you could open up Time Machine to restore a specific folder or the whole backup from the step one:

How To Downgrade Macos Big Sur To Catalina

  1. Launch Time Machine from Applications.
  2. Simply scroll all backup versions to find the file you’re looking for.
  3. Click Restore.

Reinstall Macos Catalina From Big Sur Mac

If you decide to restore the whole backup, make sure to then repeat the whole process to optimize your Mac and reinstall macOS Catalina as detailed above. The good thing is that more often than not the reinstallation works wonders right from the first time.