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How to create a bootable USB installer on macOS

Published: 08 July 2019
Updated: 23 April 2020
Filed Under: macOS

If you would like to perform a clean install of macOS or update multiple machines, it's a good idea to create a bootable USB installer. The instructions vary just slightly based on which version you're trying to setup.

Download macOS

You can download the latest release of macOS from the App Store. Or you can view the guide on how to download macOS from the command line. After downloading macOS, if the install program automatically runs, do not proceed with the installation, cancel and close it.

Prepare the USB drive

Plugin the USB drive, launch the Disk Utility app, select your USB drive on the left and click the erase button. You can leave the default name Untitled since it will be renamed automatically in the next step. Sometimes erasing the disk fails and requires two attempts to succeed.

Setup the install media

Depending on which version of macOS you are creating a USB installer for, run the appropriate command from the options below. If you changed the name of your volume, be sure to replace the word Untitled with the correct name.

macOS 10.15 Catalina

sudo /Applications/Install\ macOS\ Catalina.app/Contents/Resources/createinstallmedia --volume /Volumes/Untitled

macOS 10.14 Mojave

sudo /Applications/Install\ macOS\ Mojave.app/Contents/Resources/createinstallmedia --volume /Volumes/Untitled

macOS 10.13 High Sierra

sudo /Applications/Install\ macOS\ High\ Sierra.app/Contents/Resources/createinstallmedia --volume /Volumes/Untitled

macOS 10.12 Sierra

sudo /Applications/Install\ macOS\ Sierra.app/Contents/Resources/createinstallmedia --volume /Volumes/Untitled --applicationpath /Applications/Install\ macOS\ Sierra.app

OS X 10.11 El Capitan

sudo /Applications/Install\ OS\ X\ El\ Capitan.app/Contents/Resources/createinstallmedia --volume /Volumes/Untitled --applicationpath /Applications/Install\ OS\ X\ El\ Capitan.app

Reboot into the installer

Hold down the option key immediately after you restart the computer. Then select the USB drive with the installer on it and the macOS installer will start.