How to create a bootable installer for macOS

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

These avant-garde 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 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 as Mac Os Extended, with at to the lowest degree 14GB of bachelor 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, ormacOS High Sierra downloads to your Applications binder every bit an app named Install macOS [version proper name]. If the installer opens afterwards downloading, quit it without continuing installation. To become the correct installer:

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

The installer for Os 10 El Capitan downloads to your Downloads folder equally a disk paradigm named InstallMacOSX.dmg. To get the installer:

  • Download using Safari, and open the disk epitome 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 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 Terminal

  1. Connect the USB wink drive or other book that you lot're using for the bootable installer.
  2. Open Terminal, which is in the Utilities folder of your Applications folder.
  3. Type or paste one of the following commands in Final. These assume that the installer is in your Applications folder, and MyVolume is the name of the USB flash drive or other book you lot're using. If information technology has a different proper name, supervene upon 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/Resource/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/Resource/createinstallmedia --book /Volumes/MyVolume

El Capitan: 

sudo /Applications/Install\ OS\ X\ El\ Capitan.app/Contents/Resources/createinstallmedia --book /Volumes/MyVolume                --applicationpath /Applications/Install\ Os\ 10\ El\ Capitan.app

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


Afterward typing the command:

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

Utilise 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 lot're installing.
    • The macOS version that came with the Mac is the primeval version information technology tin can utilise.
    • A bootable installer doesn't download macOS from the internet, but 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 push until you 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 internet and uniform with the version of macOS you're installing.
    • The macOS version that came with the Mac is the primeval version it tin employ.
    • A bootable installer doesn't download macOS from the internet, 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) ⌥ cardinal immediately afterwards turning on or restarting the Mac.
  3. Release the Option central when you come across a nighttime screen showing your bootable volumes.
  4. Select the volume containing the bootable installer. And then click the up arrow or press Return.
    If y'all tin can't start upward from the bootable installer, make sure that Startup Security Utility is set to allow booting from external or removable media.
  5. Cull your language, if prompted.
  6. Select Install macOS (or Install OS 10) from the Utilities window, and then click Continue and follow the onscreen instructions.

Larn more

For data nigh the createinstallmedia control and the arguments you can use with it, brand sure that the macOS installer is in your Applications binder, and so enter the appropriate path in Terminal:

/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\ High\ Sierra.app/Contents/Resources/createinstallmedia              
/Applications/Install\ Bone\ X\ El\ Capitan.app/Contents/Resources/createinstallmedia

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