Make sure that your Mac has a connection to the internet. Then turn on your Mac and immediately press and hold Command (⌘)-R until you see an Apple logo or other image. If you're asked to select a user you know the password for, select the user, click Next, then enter their administrator password. Learn how to reinstall the operating system on your Mac, using macOS Recovery.To learn more about this topic, visit the follow article:How to reinstall macOS.

macOS Catalina is slightly outdated since the release of macOS Big Sur in November of 2020.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.

Once your Mac has booted, try re-running the ‘diskutil list’ Terminal command, to see whether this has resolved the issue. Installing macOS via Internet Recovery. Even if you can’t repair your Mac’s recovery partition, don’t panic! As long as you have an active Internet connection, you can reinstall macOS via Internet Recovery instead.

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.

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.

Reload Mac Os Mojave

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

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.

Start up from macOS Recovery

Determine whether you're using a Mac with Apple silicon, then follow the appropriate steps:

Apple silicon

Turn on your Mac and continue to press and hold the power button until you see the startup options window. Click the gear icon labelled Options, then click Continue.

Intel processor

Make sure your Mac is connected to the Internet. Then turn on your Mac and immediately press and hold Command (⌘)-R until you see an Apple logo or other image.

If you're asked to select a user you know the password for, select the user, click Next and enter their administrator password.

Reinstall macOS

Select Reinstall macOS from the utilities window in macOS Recovery, then click Continue and follow the onscreen instructions.

Reload Mac Os From Usb

Follow these guidelines during installation:

• If the installer asks to unlock your disk, enter the password you use to log in to your Mac.
• If the installer can't see your disk or notifies you that it can't install macOS on your computer or volume, you may need to erase your disk first.
• If the installer offers you the choice between installing on Macintosh HD or Macintosh HD – Data, choose Macintosh HD.
• Allow installation to complete without putting your Mac to sleep or closing its lid. Your Mac may restart and show a progress bar several times, and the screen may be empty for minutes at a time.

When the installation is complete, your Mac may restart to a setup assistant. If you're selling, trading in or giving away your Mac, press Command-Q to quit the assistant without completing setup. Then click Shut Down. When the new owner starts up the Mac, they can use their own information to complete the setup process.

Reload Macos From Scratch

Other macOS installation options

When you install macOS from Recovery, you get the current version of the most recently installed macOS, with some exceptions:

Reload Mac Os Big Sur

• On an Intel-based Mac: if you use Shift-Option-Command-R during startup, you'll be offered the macOS that came with your Mac, or the closest version that is still available. If you use Option-Command-R during startup, in most cases you'll be offered the latest macOS that is compatible with your Mac. Otherwise you'll be offered the macOS that came with your Mac, or the closest version that is still available.
• If the Mac logic board was just replaced, you may only be offered the latest macOS that is compatible with your Mac. If you've just erased your entire startup disk, you may only be offered the macOS that came with your Mac, or the closest version that is still available.

You can also use these methods to install macOS, if the macOS is compatible with your Mac:

Reload Mac Os Macbook Pro

• Use the App Store to download and install the latest macOS.
• Use the App Store or a web browser to download and install an earlier macOS.
• Use a USB flash drive or other secondary volume to create a bootable installer.