How to download and install macOS
Download and install current or previous versions of the Mac operating system on compatible Mac computers.
To maintain your computer's security, stability, and compatibility, Apple recommends using the latest macOS that is compatible with your Mac. macOS updates and upgrades also include the latest features and built-in apps such as Safari.
Use Software Update
Software Update is the fastest and easiest way to get macOS updates and upgrades, and it can use less storage space to download and install them.
Software Update shows only software that is compatible with your Mac. If Software Update says that your Mac is up to date, then no new software is currently available for your Mac model.
Use macOS Recovery
If you want to reinstall macOS, or your Mac doesn't start up all the way because it doesn't have a working operating system, you can use the built-in Recovery system to reinstall macOS.
Use the App Store
To download macOS from the App Store, you must download from a Mac that is compatible with that macOS. If your Mac isn't compatible, the App Store dims the Get button, says that the macOS is not compatible with this device, or says that the requested version of macOS is not available.
Use these links to find macOS in the App Store. If these links don't work as expected, try again using Safari, which is in your Applications folder.
Cick the Get button in the App Store to begin downloading. Software Update might open and ask you to download from there.
After downloading to your Applications folder, the installer opens automatically. Follow the onscreen installation instructions. Or quit without installing to leave the installer in your Applications folder for later use.
Use a web browser for older versions
These older macOS versions are available as disk images that you can download using your web browser. To get the installer from the disk image, you must use a Mac that is compatible with that macOS.
Use these links to download a macOS disk image (.dmg) file. If these links don't work as expected, try again using Safari, which is in your Applications folder.
Double-click the .dmg file to open it and see the package (.pkg) file within.
Double-click the .pkg file, then follow the onscreen instructions to install the macOS installer into your Applications folder.
Open your Applications folder and double-click the macOS installer, named Install [Version Name]. Follow the onscreen installation instructions.
Use a bootable installer
A bootable installer can be useful if you want to install macOS on multiple computers without downloading the installer each time, or when you can't install using macOS Recovery or the other methods.
To download an installer suitable for creating a bootable installer, use the App Store or use a web browser to download from a compatible Mac. The Mac must also be using macOS High Sierra or later, the latest version of macOS Sierra, or the latest version of OS X El Capitan.