There are a few reasons why you might want to reinstall macOS (or even Mac OS X). Maybe your Mac is working poorly and you think that a clean install of the operating system can solve the issue.
Alternatively, you may be planning to sell your Mac, or pass it on to a family member (in which case, you should first erase and restore your Mac to factory settings).
It’s even possible to reinstall the version of macOS that shipped with your Mac – which may enable you to revert to an older version of the operating system if the latest version upsets you.
Whatever your reason for installing macOS, we’ll show you one of the simplest ways to do it below.
Our method involves using the Recovery partition where you can reinstall the latest version of macOS that you have installed on your Mac. Since macOS is usually installed via Software Update (or previously the Mac App Store) there are no physical installation disks, so Apple has made it possible to install the operating system over the internet using Recovery HD.
An alternative option is to create a bootable installation of macOS on an external drive. If your Mac doesn’t boot into Recovery mode, read this: Mac can’t access Recovery mode.
You may also find this useful: How to do a clean install of macOS using a bootable drive.
How to reinstall macOS via Recovery
- Tools needed: A back up (if you delete the Mac), an Internet connection, a network with WEP or WPA security
Back up your Mac
If you’re planning to wipe your Mac as part of this process (either because you think a clean slate might fix the issues you’re having, or because you’re selling the Mac) you can back up your important documents first.
How you do this will depend on whether you want to restore your Mac to the same version of the Mac operating system, or whether you’re hoping to do a clean install. For example, if you want to revert to an older version of macOS you don’t want to back up with Time Machine. For more advice read: How to back up a Mac and Best Mac back up software.
Note, if you want to use iCloud Drive to sync all your Documents and Desktop to the cloud you may find you don’t need a backup, but make sure everything is in iCloud before you delete!
Erase your drive (M1 and M2-series Macs)
If you’re planning to sell or pass on your Mac, or you want to do a clean install of macOS to fix issues with your Mac, you’ll want to wipe your hard drive before installing the operating system. system.
If you are running macOS Monterey or a later version of macOS on a Mac with an M-series chip, or an Intel-powered Mac with a T2 chip (some Macs since 2018), there is a simple way to delete your Mac without requiring you to use Recovery mode and Disk Utilities. If you have an Intel Mac you should follow the steps below to wipe your disk before you start.
We’ve detailed how to root your Mac using this method in a separate article, but here’s a summary:
In Ventura or later:
- Open System Settings.
- Click on General.
- Select Transfer or Reset.
- Select Erase All Content and Settings.
- Set your password
- Open System Preferences.
- Click on System Preferences in the menu bar at the top of your screen.
- Click on Erase All Content and Settings.
- Set your password.
The rest of the process is the same:
- You’ll be reminded to create a Time Machine backup before you begin the removal—but you can skip that step.
- A window will show you what to remove, including Apple ID, Touch ID, accessories, and Find My settings.
- Finally you need to log out of your Mac and all related services using your Apple ID.
- Before erasing your Mac you will receive one last warning, so if you have second thoughts at least you can stop at this point!
- Clicking on the second Erase All Content and Settings will restart your Mac. Eventually you will see a black screen as it restarts.
- Once your Mac restarts you can go through the steps to set it up anew, or you can leave this stage for the next owner to set up. Just turn off the Mac first.
Unfortunately if your Mac doesn’t have Monterey installed or doesn’t have a T2 or M-series chip then you’ll need to use Disk Utility to wipe your Mac. Follow the next two steps to do that…
Once you’ve wiped your Mac the next step will show you how to enter Recovery mode.
Enter Recovery mode
The process of entering Recovery mode depends on the Mac you are using.
On a Mac with an Intel processor you need to press and hold the Command and R buttons during startup until you hear the startup sound and see a spinning globe or the Apple logo.
On a Mac that uses Apple’s own processors, such as an M1 or M2 chip, you enter Recovery mode by pressing and holding the power button while your Mac is starting up and continuing to press and hold the button until you see a startup options window will appear with an Options icon. Then select Options and click Continue.
The macOS Utilities window will open, like the one above, where you’ll see options to Restore From Time Machine Backup, Reinstall macOS [version], Safari (or Get Help Online in older versions) and Disk Utility. Your next step depends on whether you need to wipe the Mac before reinstalling the operating system. If you want to erase your disk click Disk Utility (otherwise you can skip the next step).
Erase your hard drive (Intel Macs without a T2 chip)
If you have a Mac with an Intel processor that doesn’t also have a T2 chip you can erase your Mac’s hard drive using Disk Utility accessed through Recovery mode (you need to access the drive through Recovery because it’s not possible which will erase the drive when you access it).
- Select Disk Utility from the Recovery mode options.
- Now select the volume you want to Delete. You may need to click View > Show All Drives before you can see the volume. Note that the process here is slightly different if you’re running macOS Catalina or Big Sur. If you are not running Catalina then you need to delete the Macintosh HD volume. If you’re running on Catalina or later there are two volumes probably called Macintosh HD and Macintosh HD-Data (or possibly Home and Home – Data). You must erase the Data volume first and then the Macintosh HD. We cover how to do it here: How to wipe and reformat your Mac. Remember that this will delete all your data so make sure your important data is backed up or stored in the cloud or on an external drive.
- The next step also depends on the version of macOS you are running. In Catalina, Mojave, Big Sur, Monterey, and possibly High Sierra (depending on your Mac) it will be APFS. But on older Macs running older versions of macOS the format should be set to Mac OS Extended (Journaled). You also need to select GUID Partition Table as Scheme. (You won’t see the Scheme option if you select volume).
- Click Erase and wait. (There are options under Security Options that allow you to remove the disk securely).
- Now select Disk Utility > Quit Disk Utility. Or just Command + Q.
Follow these steps to reinstall the latest version of macOS installed on your Mac:
- Return to Recovery and select Install macOS from the list of options.
- Click Continue.
- Enter your Apple ID if necessary and wait while macOS is reinstalled. Expect it to take a while.
- If you want to sell or pass on the Mac so that the next owner can enter their own details, when the setup wizard starts. If not, follow the instructions to continue setting up your Mac.
How to reinstall an older version of macOS
If you want to go back to an older version of macOS, maybe because you don’t like the latest version you have installed, there are a few ways to reinstall the older version. We separate them here: How to install older versions of macOS or OS X.
How to connect to the internet in macOS Recovery mode
To reinstall macOS using Recovery mode you must be connected to the internet. Follow these steps to connect to the internet in Recovery mode if your Mac doesn’t connect automatically:
- Click the Wi-Fi menu in the upper right corner of the screen.
- Select a Wi-Fi network.
- Enter the Wi-Fi password (if necessary).
The recovery mode must be connected to the internet and able to download the macOS installation software.
If you are using Internet recovery you must use a network with WEP or WPA security. This is not an issue as it is with most home Wi-Fi networks, but if you are on a proxy network or PPPoE then you will have problems.