How to create a bootable installer for macOS

Yous can use an external drive or secondary volume as a startup disk from which to install the Mac operating system.

These avant-garde steps are primarily for system administrators and others who are familiar with the control line. You don't need a bootable installer to upgrade macOS or reinstall macOS, but it tin can exist useful when you want to install on multiple computers without downloading the installer each time.

What you need to create a bootable installer

  • A USB wink drive or other secondary volume formatted as Mac OS Extended, with at least 14GB of available storage
  • A downloaded installer for macOS Monterey, Large Sur, Catalina, Mojave, Loftier Sierra, or El Capitan

Download macOS

The installer for macOS Monterey, macOS Big Sur, macOS Catalina, macOS Mojave, or macOS High Sierra downloads to your Applications folder every bit an app named Install macOS [version proper name]. If the installer opens afterwards downloading, quit it without standing installation. To become the right installer:

  • Download on a Mac that is uniform with that version of macOS.
  • Download on a Mac that is using macOS Sierra 10.12.v or later, or OS X El Capitan 10.11.vi.
  • Enterprise administrators: Download from Apple, not a locally hosted software-update server.

The installer for Bone X El Capitan downloads to your Downloads folder as a disk epitome named InstallMacOSX.dmg. To get the installer:

  • Download using Safari, and open the disk prototype on a Mac that is compatible with Bone X El Capitan.
  • Within the deejay 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, not from the disk epitome or .pkg installer.

Apply the 'createinstallmedia' command in Terminal

  1. Connect the USB wink drive or other volume that y'all're using for the bootable installer.
  2. Open Concluding, which is in the Utilities folder 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 proper name of the USB flash drive or other book you're using. If it has a unlike proper name, supersede MyVolume  in these commands with the proper noun of your volume.

Monterey:* 

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

Big Sur:* 

sudo /Applications/Install\ macOS\ Large\ Sur.app/Contents/Resource/createinstallmedia --volume /Volumes/MyVolume

Catalina:* 

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

Mojave:* 

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

High Sierra:* 

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

El Capitan: 

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

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


Subsequently typing the command:

  1. Press Return to enter the command.
  2. When prompted, blazon your administrator countersign and press Return again. Final doesn't show any characters as y'all blazon your password.
  3. When prompted, typeY to confirm that you want to erase the book, then press Return. Terminal shows the progress as the volume is erased.
  4. After the volume is erased, y'all may meet an alert that Terminal would like to admission files on a removable book. Click OK to permit the copy to proceed.
  5. When Terminal says that it's done, the volume will have the same name as the installer you downloaded, such as Install macOS Monterey. You can now quit Concluding and eject the volume.
    Terminal window showing completed process

Use the bootable installer

Apple tree silicon

  1. Plug the bootable installer into a Mac that is connected to the internet and compatible with the version of macOS you lot're installing.
    • The macOS version that came with the Mac is the earliest version it can apply.
    • A bootable installer doesn't download macOS from the internet, merely it does require an net connection to get firmware and other data specific to the Mac model.
  2. Turn on the Mac and continue to concord the power button until y'all run into the startup options window, which shows your bootable volumes.
  3. Select the volume containing the bootable installer, then click Go on.
  4. When the macOS installer opens, follow the onscreen instructions.

Intel processor

  1. Plug the bootable installer into a Mac that is connected to the internet and uniform with the version of macOS you're installing.
    • The macOS version that came with the Mac is the earliest version it can apply.
    • A bootable installer doesn't download macOS from the internet, only information technology does crave an internet connectedness to get firmware and other data specific to the Mac model.
  2. Press and hold the Option (Alt) ⌥ primal immediately later turning on or restarting the Mac.
  3. Release the Option key when yous see a dark screen showing your bootable volumes.
  4. Select the volume containing the bootable installer. Then click the up pointer or press Return.
    If you can't start up from the bootable installer, make certain that Startup Security Utility is set to permit booting from external or removable media.
  5. Cull your language, if prompted.
  6. Select Install macOS (or Install OS X) from the Utilities window, then click Go on and follow the onscreen instructions.

Learn more

For information about the createinstallmedia command and the arguments you lot tin utilize with it, make sure that the macOS installer is in your Applications binder, then enter the appropriate path in Terminal:

/Applications/Install\ macOS\ Monterey.app/Contents/Resources/createinstallmedia              
/Applications/Install\ macOS\ Big\ Sur.app/Contents/Resource/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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