How to create a bootable installer for macOS

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

These advanced steps are primarily for system administrators and others who are familiar with the control line. Yous don't need a bootable installer to upgrade macOS or reinstall macOS, but it tin can be useful when yous desire 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 Bone Extended, with at least 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 Big Sur, macOS Catalina, macOS Mojave, or macOS Loftier Sierra downloads to your Applications binder as an app named Install macOS [version name]. If the installer opens later on 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 10.12.v or after, or OS 10 El Capitan 10.11.6.
  • Enterprise administrators: Download from Apple, not a locally hosted software-update server.

The installer for Bone X El Capitan downloads to your Downloads binder as a disk prototype named InstallMacOSX.dmg. To go the installer:

  • Download using Safari, and open the disk image on a Mac that is uniform with OS X El Capitan.
  • Inside the disk epitome is an installer named InstallMacOSX.pkg. It installs an app named Install Bone X El Capitan into your Applications folder. You will 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 flash bulldoze 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 i of the post-obit commands in Terminal. These assume that the installer is in your Applications folder, and MyVolume is the proper name of the USB flash bulldoze or other volume y'all're using. If it has a dissimilar proper name, supplant MyVolume  in these commands with the name of your volume.

Monterey:* 

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

Large Sur:* 

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

El Capitan: 

sudo /Applications/Install\ Bone\ 10\ 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 statement and installer path, like to the fashion this is done in the command for El Capitan.


Later typing the command:

  1. Printing Return to enter the control.
  2. When prompted, type your administrator password and press Return again. Terminal doesn't testify any characters as you type your password.
  3. When prompted, typeY to confirm that you lot want to erase the book, then printing Render. Final shows the progress as the book is erased.
  4. Subsequently the volume is erased, you may see an alert that Concluding would similar to admission files on a removable book. Click OK to allow the copy to proceed.
  5. When Terminal says that it's washed, the volume volition have the same name equally the installer you downloaded, such equally Install macOS Monterey. You lot tin now quit Terminal and eject the book.
    Terminal window showing completed process

Use the bootable installer

Apple silicon

  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 earliest version information technology can use.
    • A bootable installer doesn't download macOS from the internet, but information technology does require an internet connection to get firmware and other data specific to the Mac model.
  2. Turn on the Mac and continue to hold the power button until you 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 cyberspace and compatible with the version of macOS you're installing.
    • The macOS version that came with the Mac is the primeval version information technology can use.
    • A bootable installer doesn't download macOS from the net, just it does require an net connection to get firmware and other information specific to the Mac model.
  2. Press and hold the Option (Alt) ⌥ key immediately subsequently turning on or restarting the Mac.
  3. Release the Option key when you run across a dark screen showing your bootable volumes.
  4. Select the volume containing the bootable installer. And then click the up pointer or press Return.
    If you can't get-go up from the bootable installer, make certain that Startup Security Utility is gear up to permit booting from external or removable media.
  5. Choose your language, if prompted.
  6. Select Install macOS (or Install Os X) from the Utilities window, then click Continue and follow the onscreen instructions.

Learn more

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

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

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