How to Reinstall macOS Using Recovery Mode

Here’s how to use Apple Recovery Mode built into macOS to reinstall the latest version of the operating system or an older version with or without erasing information from your Mac. Tips and tricks.

There are several reasons why you may want to reinstall the macOS operating system on your Mac, either because the computer is behaving erratically and you think that a clean installation could solve the problem, or to sell your Mac.

You should know that it is even possible to reinstall the original version of macOS with which the Mac once came, returning to a previous version with which your computer probably no longer works.

Regardless of why you want to reinstall macOS, here are some of the simplest ways to do it, and we will show you below one of the simplest ways to do it.

The method is to use the recovery partition, through which you can reinstall the latest version of macOS installed on your Mac. There are no physical installation discs because macOS is installed through the software update (or previously the Mac App Store).

For this reason, Apple has made it possible to install the operating system over the Internet using recovery HD mode. Another alternative option would be to create a bootable installation on an external drive or pen drive.

If your Mac’s Recovery Mode isn’t working, follow the steps in this article:
How to Access Terminal via Recovery Mode for Mac
How to Enter Recovery Mode on a Mac with Apple Silicon (M1) Processor
How to Enter Recovery Mode on an Intel-Based Mac

What do you need to reinstall macOS using Recovery mode?

The first thing is to have a backup. If you plan to clean your Mac by installing the operating system from scratch to fix your problems, you should know that you are interested in making a previous backup of your most important documents.

Here is a guide that you can use: How to Backup a Mac in Simple Steps

How you do this will depend on whether you want to recover your Mac with the same version or whether you want a clean installation. If you use iCloud Drive to sync your documents and desktop to the cloud, you may not need a backup.

In addition to the Internet connection, you will need to use a Wifi network with WEP or WPA security if you are using recovery mode. It’s something that most home wireless networks do, but if you’re on a proxy or PPPoE network, then you’ll have problems.

How to Reinstall macOS via ‘Recovery’ Mode

Follow these steps to reinstall the latest version of macOS:

1. Boot your Mac by holding down the ‘Command + R‘ keys until you hear the home doorbell and see the spinning earth or the Apple logo.
2. A ‘macOS Utilities‘ window will open. The next step depends on whether you want to clean up your Mac before reinstalling the operating system, or if you want to clean up your disk. Click on ‘Disk Utility’ or skip to step 8.
3. Once the ‘Disk Utility‘ is selected, click ‘Continue‘.
4. Now select the volume you want to delete. You may need to click ‘View > Show All Drives’ before viewing the volume. Note that the process here is slightly different if you’re running macOS Catalina. If you are running Catalina, there will be two volumes called Macintosh HD and Macintosh HD-Data. You will need to erase the Data volume first and then the Macintosh HD volume. If it doesn’t work with Catalina, then you just need to erase the Macintosh HD volume.
5. The next step also depends on the version of macOS you’re running. In Mojave and Catalina, and potentially in High Sierra (depending on your Mac) it will be APFS. But on Macs with older versions of macOS, the format must be set to Mac OS Extended (Journaled). You will need to have the ‘Partition Table’ GUID selected as a Schema.
6. Click on ‘Erase‘ and wait. (There are features to erase the disk safely.)
7. Now choose ‘Disk Utility > Exit Disk Utility‘. Or just tap on ‘Command + Q‘.
8. You will see the utilities screen again, choose ‘Reinstall macOS‘.
9. After clicking ‘Reinstall macOS‘, click ‘Continue’.
10. Enter your Apple ID if necessary and wait while MacOS is reinstalled. Expect this to take a while.
11. When the setup wizard starts, leave at this point if you intend to sell your Mac or give it to a family member so that the next owner can enter their own data. Otherwise, continue to set it up.

How to Install an Old Version of macOS Using Recovery Mode

In addition to the ‘Command + R‘ key combination we mentioned above, there are a couple more key combinations you can use to reinstall macOS using recovery mode.

These will allow you to choose between installing the latest version of macOS compatible with your Mac or going back to the version of macOS that was initially marketed with your Mac.

You can choose between them:

• ‘Command + R‘ will install the latest version installed on your Mac. It won’t update you to the latest version.
• ‘Option/Alt + Command + R‘ will update you to the latest version of macOS compatible with your Mac. Note: If you’re not running Sierra 10.12.4 or later, this will install the version that came with your Mac; If your Mac has a T2 chip, with ‘Option/Alt + Command + R’ you will install the latest version of macOS on your Mac.
• ‘Shift + Option/Alt + Command R‘ (if you’re running Sierra 10.12.4 or later) will install the version of MacOS that came with your Mac, or the closest one available.

Follow the steps in the previous section to reinstall macOS via Recovery.  

How to Connect to the Internet on macOS with Recovery Mode

To reinstall macOS using recovery mode, you must have an Internet connection. Follow these steps to connect to the Internet in recovery mode if your Mac doesn’t connect automatically:

1. Click the Wi-Fi menu in the upper-right corner of the screen.
2. Select the Wi-Fi network you want to use.
3. Enter the password if necessary.

Recovery mode should now be connected to the Internet to be able to download the macOS installation software.