There are times when your Mac just isn't working right. Fortunately, Apple makes it easy to reinstall macOS Catalina. All you need is an internet connection, and you're set.
Before You Reload macOS
Any time you alter your computer's operating system, there is a certain amount of risk. Therefore, it's a good idea to back up any important files you have prior to reinstalling. Fortunately, there are easy ways you can do that.
It's important that you have a reliable internet connection, either from Wi-Fi or Ethernet, as your Mac will be downloading all the files it needs for the reinstall from the internet. Additionally, if you're doing this on a laptop, be sure the laptop's power cord is plugged in.
How to Fresh Install macOS Catalina
Apple built a recovery mode into macOS for cases where you need to reinstall your operating system. This is handy when your Mac computer isn't behaving correctly or has started to slow down.
When you're ready to reinstall Catalina, it's a simple enough process.
Reinstalling macOS Catalina from recovery mode shouldn't affect any of your saved files; it simply replaces the OS with a brand new copy.
Click the Apple logo and select Restart.
As soon as the computer starts to shut down, hold down Command+R. Continue holding these keys past the black screen and/or music you hear when the computer boots up (depending on how old the Mac is) until you see Recovery Mode. Then release the keys.
You may be prompted to select a user you know the password for. Click the user and click Next.
Enter the password for the user you selected.
Click Reinstall MacOS > Continue.
Click Agree to agree to the software license agreement.
Select the disk where you want to install the operating system. In some cases, you may need to unlock the drive. Click Install or Unlock.
If you had to click "Unlock," enter the password for an administrator on the computer. Usually, it is the same password as the one you entered in Step 4.
If you had to unlock, now click Install.
The computer takes a while to download and install the operating system. Expect to wait 15 to 25 minutes, depending on the speed of your internet connection and computer. When the installation is complete, your computer restarts.
Any slowdowns or other issues you noticed should be cleared up. If not, think about completely reinstalling everything. Fortunately, there are ways to do that, too.
After Reinstalling macOS Catalina
After you complete the reinstall, check for updates to make sure you have all the latest software.
Click the Apple logo and select System Preferences in the drop-down menu.
Click Software Update.
Your Mac checks to make sure you have the latest software installed. If so, it lets you know. Otherwise, it prompts you to install any updates that are available.