These advanced steps are primarily for system administrators and people who are familiar with the command line. You don't need a bootable installer to upgrade macOS or reinstall macOS, but it can be useful when you want to install it on multiple computers without having to download 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 12 GB of available storage; A downloaded installer for macOS Big Sur, Catalina, Mojave, High Sierra or El Capitan.

Step 3.6: USB Patch for High Sierra. The config.plist needs a USB patch for High Sierra and the patch is different for each version of macOS High Sierra 10.13.0 to 10.13.6. A patch is included for 10.13.6 so those that downloaded from the App Store don’t need to add any patch. There are two main things you'll need to make your bootable install drive: a USB stick (or a Thunderbolt drive) and the installation files. Mojave or High Sierra installed it's a little tricky. I saw it is possible to revert APFS to HFS with a usb stick, and I tried and I done it. BUT how can I do it for the main hdd? Another issue is that bootable USB of High Sierra I created is not working, as, when I do ALT after restart, the Mac does not see the usb drive (I guess because it is formatted in journaled, hence HFS). A bootable USB is super convenient to have on hand if you need to install or repair an operating system on your computer. You can easily make your own bootable USB that's equipped with the operating system of your choosing.

  • A USB flash drive or other secondary volume, formatted as Mac OS Extended, with at least 12 GB of available storage
  • A downloaded installer for macOS Big Sur, Catalina, Mojave, High Sierra or El Capitan

Download macOS

  • Download: macOS Big Sur, macOS Catalina, macOS Mojave or macOS High Sierra
    These will be downloaded to your Applications folder as an app called Install macOS [version name]. If the installer opens after download, quit it without continuing the installation. To get the correct installer, download from a Mac that is using macOS Sierra 10.12.5 or later, or El Capitan 10.11.6. For enterprise administrators, please download from Apple, not a locally hosted software update server.
  • Download: OS X El Capitan
    This will be downloaded as a disk image called InstallMacOSX.dmg. On a Mac that is compatible with El Capitan, open the disk image and run the installer within, which has the name InstallMacOSX.pkg. It installs an app named Install OS 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

Bootable Usb Stick High Sierra
  1. Connect the USB flash drive or other volume that you'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 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're using. If it has a different name, replace MyVolume in these commands with the name of your volume.

Big Sur:*

Catalina:*

Bootable usb stick high sierra

Mojave:*

Bootable Usb Stick High Sierra Free

High Sierra:*

High

El Capitan:

* If your Mac is using macOS Sierra or earlier, include the --applicationpath argument and installer path, similar to the way this was 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 press Return again. Terminal doesn't show any characters as you type your password.
  3. When prompted, type Y to confirm that you want to erase the volume, then press Return. Terminal displays the progress as the volume is being erased.
  4. After the volume has been erased, you may see an alert stating that Terminal would like to access files on a removable volume. Click OK to allow the copy to proceed.
  5. When Terminal says it's finished, the volume will have the same name as the installer you downloaded, such as Install macOS Big Sur. You can now quit Terminal and eject the volume.

Use the bootable installer

Determine whether you're using a Mac with Apple silicon, then follow the appropriate steps:

Apple silicon

Bootable Usb Stick High Sierra
  1. Plug the bootable installer into a Mac that is connected to the Internet and compatible with the version of macOS you're installing.
  2. Turn on your Mac and continue to hold the power button until you see the startup options window, which shows your bootable volumes and a gear icon labelled Options.
  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.
  2. Press and hold the Option (Alt) ⌥ key immediately after turning on or restarting your Mac.
  3. Release the Option key when you see a dark screen displaying your bootable volumes.
  4. Select the volume containing the bootable installer. Then click the up arrow or press Return.
    If you can't start up from the bootable installer, make sure the External Boot setting in Startup Security Utility has been set to allow booting from external 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 more information about the createinstallmedia command and the arguments that you can use with it, make sure the macOS installer is in your Applications folder, then enter the appropriate path in Terminal:

Bootable Usb Stick Mac High Sierra

  • Big Sur: /Applications/Install macOS Big Sur.app/Contents/Resources/createinstallmedia
  • Catalina: /Applications/Install macOS Catalina.app/Contents/Resources/createinstallmedia
  • Mojave: /Applications/Install macOS Mojave.app/Contents/Resources/createinstallmedia
  • High Sierra: /Applications/Install macOS High Sierra.app/Contents/Resources/createinstallmedia
  • El Capitan: /Applications/Install OS X El Capitan.app/Contents/Resources/createinstallmedia

Bootable Usb Stick High Sierra Software

High

Bootable Usb Stick High Sierra Download

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.