The program used to create a bootable drive ( createinstallmedia) is supplied as part of the installer App. You could name the drive to something different as long as you adjust the command line syntax below to match. The Terminal commands below assume that the drive is named Untitled. Name the drive ' Untitled' this name will be changed when the new volume is initialised. The drive must be formatted as a Mac OS Extended (Journaled) volume with a GUID Partition Table. This can be a hard drive, an SSD, or a USB stick. You need a Mac-formatted drive big enough to hold the installer and its data - 12 GiB. Then copy the installer App somewhere else so that you won't have to download it again.Īt the command line, spaces must be escaped so these become: Therefore your first step after downloading the installer should be to cancel the install. If you run the macOS installer from the /Applications folder, the installer app will be deleted. MacOS is distributed through the App Store which will download an installer app to the /Applications folder. Use a USB flash drive (or other removable media) as a startup disk from which to install macOS.