How to create a bootable installer for macOS

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

These advanced steps are primarily for organization administrators and others who are familiar with the control line. You don't need a bootable installer to upgrade macOS or reinstall macOS, but information technology 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 every bit Mac Bone Extended, with at to the lowest degree 14GB of available storage
  • A downloaded installer for macOS Monterey, Big Sur, Catalina, Mojave, High Sierra, or El Capitan

Download macOS

The installer for macOS Monterey, macOS Large Sur, macOS Catalina, macOS Mojave, or macOS High Sierra downloads to your Applications binder as an app named Install macOS [version name]. If the installer opens after downloading, quit it without continuing 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 on, or OS X El Capitan 10.eleven.half-dozen.
  • Enterprise administrators: Download from Apple, non a locally hosted software-update server.

The installer for Bone X El Capitan downloads to your Downloads folder as a deejay prototype named InstallMacOSX.dmg. To become the installer:

  • Download using Safari, and open the deejay epitome on a Mac that is uniform with OS 10 El Capitan.
  • Inside the deejay prototype is an installer named InstallMacOSX.pkg. It installs an app named Install OS 10 El Capitan into your Applications binder. You will create the bootable installer from this app, not from the disk epitome or .pkg installer.

Use the 'createinstallmedia' command in Terminal

  1. Connect the USB flash 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 binder.
  3. Type or paste one of the post-obit commands in Final. These assume that the installer is in your Applications folder, and MyVolume is the proper noun of the USB flash drive or other volume you lot're using. If information technology has a different name, replace MyVolume  in these commands with the proper noun of your volume.

Monterey:* 

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

Large Sur:* 

sudo /Applications/Install\ macOS\ Large\ 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 --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 earlier, include the--applicationpath statement and installer path, similar to the way this is done in the control for El Capitan.


Afterwards typing the command:

  1. Press Return to enter the control.
  2. When prompted, type your administrator password and printing Render once again. Terminal doesn't show any characters as yous type your countersign.
  3. When prompted, typeY to ostend that you want to erase the book, and then press Render. Concluding shows the progress as the volume is erased.
  4. After the volume is erased, you lot may see an alarm that Final would like to access files on a removable volume. Click OK to allow the copy to proceed.
  5. When Terminal says that it'due south done, the book volition have the aforementioned name as the installer you downloaded, such equally Install macOS Monterey. You tin now quit Terminal and eject the volume.
    Terminal window showing completed process

Use 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 utilise.
    • A bootable installer doesn't download macOS from the internet, merely information technology does require an net connectedness to get firmware and other data specific to the Mac model.
  2. Plow on the Mac and keep to hold the power button until y'all come across 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 internet and compatible with the version of macOS you're installing.
    • The macOS version that came with the Mac is the primeval version information technology tin use.
    • A bootable installer doesn't download macOS from the net, but it does crave an internet connection to get firmware and other information specific to the Mac model.
  2. Press and hold the Choice (Alt) ⌥ key immediately after turning on or restarting the Mac.
  3. Release the Option key when you lot see a dark screen showing your bootable volumes.
  4. Select the book containing the bootable installer. Then click the upwardly arrow or press Return.
    If you tin't start upwards 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 Bone X) from the Utilities window, then click Proceed and follow the onscreen instructions.

Learn more than

For information about the createinstallmedia command and the arguments you can utilise with it, make sure that the macOS installer is in your Applications folder, then 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/Resources/createinstallmedia              
/Applications/Install\ macOS\ Mojave.app/Contents/Resource/createinstallmedia              
/Applications/Install\ macOS\ Loftier\ Sierra.app/Contents/Resources/createinstallmedia              
/Applications/Install\ Os\ 10\ El\ Capitan.app/Contents/Resources/createinstallmedia

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