Press and hold the Option (Alt) ⌥ key immediately after turning on or restarting your Mac.When the macOS installer opens, follow the onscreen instructions.Select the volume containing the bootable installer, then click Continue.Turn on your Mac and continue to hold the power button until you see the startup options window, which shows your bootable volumes and a gear icon labled Options.Plug the bootable installer into a Mac that is connected to the internet and compatible with the version of macOS you're installing.If it has a different name, replace MyVolume in these commands with the name of your volume.ĭetermine whether you're using a Mac with Apple silicon, then follow the appropriate steps: Apple silicon These assume that the installer is in your Applications folder, and MyVolume is the name of the USB flash drive or other volume you're using. Type or paste one of the following commands in Terminal.Open Terminal, which is in the Utilities folder of your Applications folder.Connect the USB flash drive or other volume that you're using for the bootable installer.Use the 'createinstallmedia' command in Terminal You will create the bootable installer from this app, not from the disk image or. It installs an app named Install OS X El Capitan into your Applications folder. On a Mac that is compatible with El Capitan, open the disk image and run the installer within, named InstallMacOSX.pkg. This downloads as a disk image named InstallMacOSX.dmg. Enterprise administrators, please download from Apple, not a locally hosted software-update server. To get the correct installer, download from a Mac that is using macOS Sierra 10.12.5 or later, or El Capitan 10.11.6. If the installer opens after downloading, quit it without continuing installation. These download to your Applications folder as an app named Install macOS. Download: macOS Big Sur, macOS Catalina, macOS Mojave, or macOS High Sierra.

A downloaded installer for macOS Big Sur, Catalina, Mojave, High Sierra, or El Capitan.A USB flash drive or other secondary volume, formatted as Mac OS Extended, with at least 12GB of available storage.

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