Reinstall Catalina

| 16-08-2021
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macOS Catalina is slightly outdated since the release of macOS Big Sur in November of 2020.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.

When you update or reinstall the macOS, the last thing you want is probably losing data on your computer. To reinstall macOS, including the latest Big Sur, Catalina, Mojave, without losing data, you can follow the professional guide to update the OS, which will not cause data loss in most of the case. MacOS Catalina (macOS 10.15) Driver Installation and Troubleshooting This describes how to install the driver for macOS Catalina (macOS 10.15) and perform troubleshooting. For information on individual products, check the listings in Readme.htm in the download file.

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.

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:

  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

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

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.

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

Reinstall Catalina

Reinstall Catalina

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:

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

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.

Easy way to Clean Install mac OS Catalina

macOS Catalina is Apple’s shiny new operating system for the Mac and it’s got a ton of great features and improvements. You’re probably keen to get started and install it straight away. Before you do, consider whether you want to install it over the top of your current OS, or as a completely clean install of macOS Catalina. The benefits of the latter are that it will be like a completely new Mac, with all your settings wiped out, and junk files gone. It should make your Mac run faster. The rest of this article will explain how to clean install macOS Catalina.

Reinstall Catalina From Usb

Before the clean installation of macOS 10.15 Catalina it’s recommended that you first delete junk and dusty files from the current macOS. There are many free and paid tools to clean junk but the quickest option is to run CleanMyMac X. You can expect to free up tens of gigabytes of space, including old apps, and their leftovers.

Here’s how it works.

  1. Download and install CleanMyMac — try a free edition of the app here
  2. Choose the System Junk tool.
  3. Press Scan.
  4. When it’s finished either press Remove to get rid of all the files it recommends, or choose Review to look through what it’s found and decide for yourself what to delete and what to keep.

Backup your Mac

I can’t stress how important this is. You must backup your Mac before you do anything else. You’re going to be erasing your startup drive completely, so you need a complete backup of everything. You can use Time Machine, another backup app, or a cloning tool. Just make sure you have a complete, preferably bootable, copy of your current installation.

You should also make notes of settings for apps you use regularly – screen grabbing them is a good way to do that. And you should make sure you have a copy of any licence codes that you’ll need when you reinstall applications. You can use Apple’s Notes app to make notes, as long as you sync them with iCloud.

Create a bootable installer of macOS Catalina

If you’re reading this after Catalina ships, you can download it from the Mac App Store and then choose Quit when the installation starts. If you’re clean installing the beta (and, by the way, that’s not something I would recommend. It’s much better to create a dual boot system when you run the beta.

  1. Grab a USB stick with a capacity of at least 16GB, or an external hard drive or USB.
  2. Go to Applications>Utilities and launch Disk Utility.
  3. Launch Disk Utilities and Erase the Drive or USB stick, formatting it as Mac OS Extended (Journaled) or APFS and selecting GUID partition map if a selection is available.
  4. The easiest method for creating a bootable installer is to use DiskMaker X. However, if you’re comfortable using Terminal, you can do it like this:
    1. Launch Terminal from Applications>Utilities
    2. Type: sudo /Applications/Install macOS Catalina Beta.app/Contents/Resources/createinstallmedia --volume /Volumes/Untitled --applicationpath /Applications/Install macOS Catalina Beta.app where ‘Untitled’ is the name of your USB stick or external hard drive
    3. Press Return and wait for the word Done to appear in Terminal.

Reinstall Catalina From Usb

Once you see ‘Done’ in Terminal you can quit it. Your USB stick or external hard drive is now a bootable Catalina installer, so keep it safe. Now, it’s time to clean install macOS Catalina.

How to Clean install macOS Catalina

Now you've made a backup and created a bootable installer, it's time to actually install the new macOS. Follow these easy steps to clean install macOS Catalina on your Mac.

  1. Plug your USB stick or external hard drive into your Mac, if it’s not plugged in already.
  2. Restart your Mac while holding down the Option key.
  3. When you see the options for booting appear on screen, choose the installer disk you just created.
  4. When you see the macOS Utilities screen appear, choose Disk Utility
  5. When Disk Utility launches, choose the Eras tab then select your startup volume (probably called Macintosh HD).
  6. Give your startup disk a name, then choose a format. If you have a recent Mac with an SSD startup disk, select APFS. If you have an older Mac with a mechanical hard drive or Fusion Drive, choose whichever one you want to use.
  7. Choose Erase.
  8. When Disk Utility has finished erasing the disk, quit it to return to the macOS Utilities screen.
  9. Choose Install macOS.
  10. Press Continue and choose the drive you just erased and re-formatted as the destination.
  11. MacOS Catalina will start to install.
  12. When it’s finished, your Mac will restart and it will look like a brand new Mac. Go through the set-up process to set up a user account, add your wifi network, choose a language, and log in to iCloud.

Once you’ve set up your Mac, you can eject the installer disk and remove it. Remember to keep it safe. You can now restore files you backed up earlier from Time Machine or whichever backup tool you used. Remember to restore files and folders individually, don’t, for example, restore your entire user directory otherwise you’ll copy back all the junk files you just got rid of. Reinstall applications and go through them adding license details where necessary. Check that everything works as you expect it to and use the screen shots you made earlier to configure settings.

Reinstall Catalina From Big Sur

There are lots of good reasons why you might want to clean install macOS Catalina, but the most important one is that it should make your Mac feel like new and keep it running smoothly. For ultimate Mac refresh you can also download CleanMyMac X and play with its cleanup tools. Getting rid of old junk feels great.