How to create a bootable installer for macOS

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

These advanced steps are primarily for arrangement administrators and others who are familiar with the command line. You lot don't need a bootable installer to upgrade macOS or reinstall macOS, simply information technology tin be useful when you want to install on multiple computers without downloading the installer each time.

What yous need to create a bootable installer

  • A USB flash drive or other secondary volume formatted as Mac OS Extended, with at least 14GB of bachelor 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 Loftier Sierra downloads to your Applications folder as an app named Install macOS [version name]. If the installer opens later downloading, quit information technology without standing installation. To become the correct installer:

  • Download on a Mac that is compatible with that version of macOS.
  • Download on a Mac that is using macOS Sierra x.12.5 or later on, or OS X El Capitan 10.xi.6.
  • Enterprise administrators: Download from Apple tree, non a locally hosted software-update server.

The installer for OS 10 El Capitan downloads to your Downloads folder every bit a disk prototype named InstallMacOSX.dmg. To go the installer:

  • Download using Safari, and open the deejay image on a Mac that is compatible with Bone X El Capitan.
  • Inside the disk image is an installer named InstallMacOSX.pkg. It installs an app named Install OS X El Capitan into your Applications folder. You volition create the bootable installer from this app, not from the disk image or .pkg installer.

Use the 'createinstallmedia' command in Concluding

  1. Connect the USB wink drive or other volume that y'all're using for the bootable installer.
  2. Open Terminal, which is in the Utilities folder of your Applications folder.
  3. Type or paste ane 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 drive or other volume you lot're using. If it has a different name, replace MyVolume  in these commands with the 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 --volume /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 --book /Volumes/MyVolume                --applicationpath /Applications/Install\ OS\ 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.


After typing the command:

  1. Press Render to enter the command.
  2. When prompted, blazon your administrator countersign and printing Return again. Terminal doesn't show any characters every bit y'all type your password.
  3. When prompted, typeY to confirm that you want to erase the volume, so press Return. Terminal shows the progress as the volume is erased.
  4. Afterward the volume is erased, you may see an alarm that Last would like to access files on a removable volume. Click OK to allow the copy to go along.
  5. When Concluding says that it's done, the volume will have the same name as the installer you downloaded, such as Install macOS Monterey. Yous can now quit Final and eject the volume.
    Terminal window showing completed process

Utilize the bootable installer

Apple silicon

  1. Plug the bootable installer into a Mac that is connected to the net and compatible with the version of macOS y'all're installing.
    • The macOS version that came with the Mac is the primeval version it can use.
    • A bootable installer doesn't download macOS from the internet, but it does require an cyberspace 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 yous see the startup options window, which shows your bootable volumes.
  3. Select the volume containing the bootable installer, and so 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 you lot're installing.
    • The macOS version that came with the Mac is the earliest version it can employ.
    • A bootable installer doesn't download macOS from the internet, but it does require an internet connection to go firmware and other information specific to the Mac model.
  2. Press and hold the Pick (Alt) ⌥ primal immediately later on turning on or restarting the Mac.
  3. Release the Option central when you run into a dark screen showing your bootable volumes.
  4. Select the volume containing the bootable installer. And so click the up arrow or press Return.
    If you lot can't start upward from the bootable installer, make certain that Startup Security Utility is fix to allow booting from external or removable media.
  5. Choose your linguistic communication, if prompted.
  6. Select Install macOS (or Install Bone X) from the Utilities window, then click Continue and follow the onscreen instructions.

Learn more

For information about the createinstallmedia command and the arguments you can apply with information technology, brand sure that the macOS installer is in your Applications binder, then enter the appropriate path in Terminal:

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

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