

Updated December 2019: Everything is up to date through macOS Catalina.If neither of these options work, don’t panic! You’ve got a couple of options yet. If you have any more questions about reinstalling macOS on your Mac, let us know in the comments. How to set up and customize your Mac from scratch Questions? If you're starting from scratch, you'll need to set up your Mac from scratch. Your Mac will now go through the normal macOS installation process, eventually restarting.

If you want the content on your Mac to stay intact, skip to the next section.

If you need to start completely fresh, then you'll want to erase your startup disk using Disk Utility. How to erase your startup disk in macOS Recovery mode First Aid will run, checking the health of your Mac's drive. It should be the drive at the top of the sidebar if there are multiple drives. Click on your Mac's startup drive in the Disk Utility sidebar.

Click Disk Utility when in macOS Recovery.You'll need to use Disk Utility to do that. The first thing you'll want to do is make sure your Mac's startup disk is healthy. How to check your startup disk with Disk Utility in macOS Recovery mode Press Shift - Option - Command - R to install the version of macOS that came with your Mac, or the version closest to it that's still available.Press Options - Command - R to upgrade to the latest version of macOS that's compatible with your Mac.Press Command - R to install the latest version of macOS that was installed on your Mac without installing a later version.
