The recovery utility can be used to do a clean install of macOS on your Mac.Make sure your Mac is connected to a power source and has a steady internet connection during the install process.
Step 1: Turn on or off your computer.
You can access recovery utility this way.If you don't have a local copy of macOS, your computer needs access to the internet.
Step 2: Right away, press and hold Cmd+R.
The key combination tells you to uninstall the macOS version that was already installed on your Mac.To upgrade to the most current OS that is compatible with your Mac, press Opt+ Cmd+R.A Mac from early 2012 will not work with Catalina.The easiest way to install the macOS on your Mac is by pressing Shift+ Opt+ Cmd+R.This key combination will not work if you didn't have Sierra.If you've never installed Sierra, using Cmd+R will install the OS without tying it to your Apple ID.Before giving your drive to someone else, use this key combination to erase it.
Step 3: The keys should be released when you see the Apple logo.
There could be a spinning globe or a prompt for you to enter a password.
Step 4: You can choose if you want to erase your disk.
If you do this, you will lose all information on your computer.If you don't want to lose everything, "Restore from Time Machine Backup" is a good option.
Step 5: Click to uninstall macOS.
This will allow you to keep your files and user settings.
Step 6: Click on Continue.
You will start the process.
Step 7: Follow the instructions on the screen.
Selecting where to install the OS is part of the process.Don't close your Mac lid or put it to sleep during the installation process.Installation isn't done if you see your Mac restart a few times, show a blank screen, and show progress bars.