How to create a bootable installer for macOS

Y'all tin use an external bulldoze or secondary volume equally a startup disk from which to install the Mac operating system.

These advanced steps are primarily for organisation administrators and others who are familiar with the command line. Y'all don't demand a bootable installer to upgrade macOS or reinstall macOS, but information technology can be useful when yous want to install on multiple computers without downloading the installer each fourth dimension.

What you need to create a bootable installer

  • A USB flash drive or other secondary volume formatted as Mac Bone Extended, with at least 14GB of bachelor storage
  • A downloaded installer for macOS Monterey, Big Sur, Catalina, Mojave, High Sierra, or El Capitan

Download macOS

The installer for macOS Monterey,macOS Big Sur,macOS Catalina,macOS Mojave, ormacOS High Sierra downloads to your Applications folder as an app named Install macOS [version name]. If the installer opens after downloading, quit it without continuing installation. To go the correct installer:

  • Download on a Mac that is compatible with that version of macOS.
  • Download on a Mac that is using macOS Sierra 10.12.5 or later, or Bone 10 El Capitan x.eleven.six.
  • Enterprise administrators: Download from Apple tree, not a locally hosted software-update server.

The installer for OS X El Capitan downloads to your Downloads folder as a deejay image named InstallMacOSX.dmg. To get the installer:

  • Download using Safari, and open the deejay image on a Mac that is compatible with OS 10 El Capitan.
  • Within the disk image is an installer named InstallMacOSX.pkg. Information technology installs an app named Install OS X El Capitan into your Applications folder. You will create the bootable installer from this app, non from the disk image or .pkg installer.

Use the 'createinstallmedia' command in Final

  1. Connect the USB flash drive or other volume that you're using for the bootable installer.
  2. Open Terminal, which is in the Utilities binder of your Applications folder.
  3. Type or paste one of the following commands in Terminal. These assume that the installer is in your Applications folder, and MyVolume is the name of the USB flash bulldoze or other volume you're using. If information technology has a different name, supercede MyVolume  in these commands with the proper name of your volume.

Monterey:* 

sudo /Applications/Install\ macOS\ Monterey.app/Contents/Resources/createinstallmedia --volume /Volumes/MyVolume

Big Sur:* 

sudo /Applications/Install\ macOS\ Big\ Sur.app/Contents/Resources/createinstallmedia --volume /Volumes/MyVolume

Catalina:* 

sudo /Applications/Install\ macOS\ Catalina.app/Contents/Resources/createinstallmedia --book /Volumes/MyVolume

Mojave:* 

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

High Sierra:* 

sudo /Applications/Install\ macOS\ Loftier\ Sierra.app/Contents/Resources/createinstallmedia --volume /Volumes/MyVolume

El Capitan: 

sudo /Applications/Install\ Os\ X\ El\ Capitan.app/Contents/Resource/createinstallmedia --volume /Volumes/MyVolume                --applicationpath /Applications/Install\ Bone\ X\ El\ Capitan.app

* If your Mac is using macOS Sierra or earlier, include the--applicationpath argument and installer path, similar to the way this is done in the command for El Capitan.


Afterwards typing the command:

  1. Printing Render to enter the command.
  2. When prompted, blazon your ambassador password and press Return again. Terminal doesn't bear witness any characters every bit y'all type your password.
  3. When prompted, typeY to confirm that you want to erase the volume, and then press Return. Final shows the progress every bit the volume is erased.
  4. After the volume is erased, you may come across an alert that Last would similar to access files on a removable volume. Click OK to permit the copy to proceed.
  5. When Terminal says that it's done, the book will accept the aforementioned name every bit the installer you downloaded, such as Install macOS Monterey. Y'all tin can at present quit Terminal and eject the volume.
    Terminal window showing completed process

Utilise the bootable installer

Apple silicon

  1. Plug the bootable installer into a Mac that is continued to the internet and compatible with the version of macOS you're installing.
    • The macOS version that came with the Mac is the earliest version it can use.
    • A bootable installer doesn't download macOS from the cyberspace, but it does crave an cyberspace connection to get firmware and other information specific to the Mac model.
  2. Turn on the Mac and go on to concord the power button until you see the startup options window, which shows your bootable volumes.
  3. Select the volume containing the bootable installer, then click Go along.
  4. When the macOS installer opens, follow the onscreen instructions.

Intel processor

  1. Plug the bootable installer into a Mac that is continued to the net and uniform with the version of macOS you're installing.
    • The macOS version that came with the Mac is the earliest version it can utilise.
    • A bootable installer doesn't download macOS from the cyberspace, only it does require an cyberspace connection to get firmware and other information specific to the Mac model.
  2. Printing and hold the Pick (Alt) ⌥ central immediately afterwards turning on or restarting the Mac.
  3. Release the Pick central when you run into a night screen showing your bootable volumes.
  4. Select the volume containing the bootable installer. And then click the up pointer or press Return.
    If you lot can't start up from the bootable installer, make sure that Startup Security Utility is set to allow booting from external or removable media.
  5. Choose your language, if prompted.
  6. Select Install macOS (or Install OS X) from the Utilities window, and then click Continue and follow the onscreen instructions.

Larn more

For information nearly the createinstallmedia command and the arguments you lot can use with it, make sure that the macOS installer is in your Applications folder, then enter the appropriate path in Terminal:

/Applications/Install\ macOS\ Monterey.app/Contents/Resources/createinstallmedia              
/Applications/Install\ macOS\ Large\ Sur.app/Contents/Resources/createinstallmedia              
/Applications/Install\ macOS\ Catalina.app/Contents/Resources/createinstallmedia              
/Applications/Install\ macOS\ Mojave.app/Contents/Resource/createinstallmedia              
/Applications/Install\ macOS\ High\ Sierra.app/Contents/Resources/createinstallmedia              
/Applications/Install\ Os\ X\ El\ Capitan.app/Contents/Resources/createinstallmedia

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