How to create a bootable installer for macOS

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

These advanced steps are primarily for system administrators and others who are familiar with the command line. You lot don't demand a bootable installer to upgrade macOS or reinstall macOS, but it can be 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 flash drive or other secondary volume formatted as Mac Os Extended, with at least 14GB of available storage
  • A downloaded installer for macOS Monterey, Big 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 as an app named Install macOS [version name]. If the installer opens after downloading, quit it without standing installation. To get the correct installer:

  • Download on a Mac that is compatible with that version of macOS.
  • Download on a Mac that is using macOS Sierra ten.12.5 or later, or OS 10 El Capitan 10.11.vi.
  • Enterprise administrators: Download from Apple, not a locally hosted software-update server.

The installer for Os Ten El Capitan downloads to your Downloads binder equally a deejay paradigm named InstallMacOSX.dmg. To go the installer:

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

Utilize the 'createinstallmedia' command in Terminal

  1. Connect the USB flash bulldoze or other volume that you're using for the bootable installer.
  2. Open Last, which is in the Utilities folder of your Applications binder.
  3. Type or paste one of the following commands in Last. These assume that the installer is in your Applications folder, and MyVolume is the name of the USB flash drive or other volume y'all're using. If it has a different proper noun, supersede MyVolume  in these commands with the proper noun 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/Resource/createinstallmedia --volume /Volumes/MyVolume

Mojave:* 

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

High Sierra:* 

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

El Capitan: 

sudo /Applications/Install\ Bone\ X\ El\ Capitan.app/Contents/Resource/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.


After typing the command:

  1. Press Return to enter the command.
  2. When prompted, type your administrator password and printing Return once more. Terminal doesn't evidence whatever characters as you blazon your password.
  3. When prompted, typeY to confirm that you want to erase the volume, then press Return. Terminal shows the progress as the volume is erased.
  4. Afterwards the volume is erased, you may encounter an alert that Terminal would like to access files on a removable volume. Click OK to let the copy to go along.
  5. When Final says that information technology's done, the volume will accept the same proper noun every bit the installer you downloaded, such as Install macOS Monterey. You can at present quit Concluding and squirt the book.
    Terminal window showing completed process

Utilise the bootable installer

Apple silicon

  1. Plug the bootable installer into a Mac that is connected to the cyberspace 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 internet, simply it does require an internet connection to get firmware and other information specific to the Mac model.
  2. Turn on the Mac and continue to hold 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 Continue.
  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 net and uniform with the version of macOS yous'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 internet, merely it does require an internet connection to go firmware and other information specific to the Mac model.
  2. Press and agree the Pick (Alt) ⌥ key immediately after turning on or restarting the Mac.
  3. Release the Choice key when you run across a dark screen showing your bootable volumes.
  4. Select the book containing the bootable installer. Then click the up arrow or press Return.
    If you lot tin can't offset upward from the bootable installer, brand 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 Ten) from the Utilities window, then click Continue and follow the onscreen instructions.

Learn more

For data well-nigh the createinstallmedia command and the arguments y'all can use with it, make certain that the macOS installer is in your Applications folder, so enter the appropriate path in Last:

/Applications/Install\ macOS\ Monterey.app/Contents/Resources/createinstallmedia              
/Applications/Install\ macOS\ Big\ Sur.app/Contents/Resources/createinstallmedia              
/Applications/Install\ macOS\ Catalina.app/Contents/Resource/createinstallmedia              
/Applications/Install\ macOS\ Mojave.app/Contents/Resources/createinstallmedia              
/Applications/Install\ macOS\ High\ Sierra.app/Contents/Resources/createinstallmedia              
/Applications/Install\ OS\ Ten\ El\ Capitan.app/Contents/Resources/createinstallmedia

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