A bootable installer can be useful when you want to install macOS on multiple computers without downloading the installer each time, or without connecting to the Internet.
These advanced steps are primarily for system administrators and others who are familiar with the command line. You don't need to create a bootable installer to install macOS.
Download macOS from the App Store
- Download macOS from the Mac App Store. It downloads to your Applications folder as a single ”Install” file, such as Install macOS High Sierra.
If you're creating a bootable installer for macOS High Sierra, download from a Mac using High Sierra, Sierra 10.12.5 or later, or El Capitan 10.11.6. Enterprise administrators: Please download from Apple, not a locally hosted software-update server.
- When the installer opens, quit it without continuing installation.
Then use the 'createinstallmedia' command in Terminal
- After downloading the installer, mount the USB flash drive or other volume that you're using for the bootable installer. Make sure that it has at least 12GB of available storage.
- Open Terminal, which is in the Utilities folder of your Applications folder.
- Type one of the following commands in Terminal. These all assume that the installer is in your Applications folder, and the name of the volume that you're using for the bootable installer is MyVolume. If your volume is named differently, replace MyVolume with the name of your volume.
sudo /Applications/Install\ macOS\ High\ Sierra.app/Contents/Resources/createinstallmedia --volume /Volumes/MyVolume
sudo /Applications/Install\ macOS\ Sierra.app/Contents/Resources/createinstallmedia --volume /Volumes/MyVolume --applicationpath /Applications/Install\ macOS\ Sierra.app
sudo /Applications/Install\ OS\ X\ El\ Capitan.app/Contents/Resources/createinstallmedia --volume /Volumes/MyVolume --applicationpath /Applications/Install\ OS\ X\ El\ Capitan.app
sudo /Applications/Install\ OS\ X\ Yosemite.app/Contents/Resources/createinstallmedia --volume /Volumes/MyVolume --applicationpath /Applications/Install\ OS\ X\ Yosemite.app
sudo /Applications/Install\ OS\ X\ Mavericks.app/Contents/Resources/createinstallmedia --volume /Volumes/MyVolume --applicationpath /Applications/Install\ OS\ X\ Mavericks.app
- Press Return after typing the command.
- When prompted, type your administrator password and press Return again. Terminal doesn't show any characters as you type your password
- When prompted, type
Yto confirm that you want to erase the volume, then press Return. Terminal shows the progress as the bootable installer is created.
- Quit Terminal when done. The bootable installer is now ready to use on a compatible Mac. Learn how to choose it as your startup disk.
For more information about the
createinstallmedia command used in the examples above, make sure that the macOS installer is in your Applications folder, then enter the appropriate path in Terminal:
/Applications/Install\ macOS\ High\ Sierra.app/Contents/Resources/createinstallmedia
/Applications/Install\ macOS\ Sierra.app/Contents/Resources/createinstallmedia
/Applications/Install\ OS\ X\ El\ Capitan.app/Contents/Resources/createinstallmedia
/Applications/Install\ OS\ X\ Yosemite.app/Contents/Resources/createinstallmedia
/Applications/Install\ OS\ X\ Mavericks.app/Contents/Resources/createinstallmedia