How to Create a Bootable USB Installer for macOS or OS X El Capitan

Make a bootable USB installer for El Capitan

Like previous versions of macOS, El Capitan (10.11) automatically begins the installation process once the download is complete.

This is fine if you want to quickly install the new OS to replace an existing one. But for a lot of users, there's a bit of housekeeping that needs to be done before installing the new OS. This may include backing up your data or making a bootable version of the El Capitan installer on a USB flash drive.

A bootable OS X Yosemite installer
Brooke Pelczynski / Lifewire 

A bootable installer for macOS El Capitan is a good idea even if your plan is to perform an upgrade install. Having your own copy of El Capitan on a separate device ensures that you'll always be able to install or reinstall it. It also helps in performing basic troubleshooting tasks, even if you have no connection to the internet or access to the Mac App Store.

El Capitan is no longer available in the App store for download; these instructions only apply if you've already downloaded it and associated it with your Apple ID.

Create a Bootable macOS El Capitan Installer on a USB Flash Drive

There are two ways create the bootable installer. One involves Disk Utility, Finder, hidden files, and a great deal of time and effort. If you wish to use this method, you can follow our guide: How to Make a Bootable Flash Installer of OS X or macOS. The older OS used in that guide will still work for El Capitan.

The other method is less involved, has fewer places where things can go wrong, and only involves a single app: Terminal.

What You Need

You'll need a copy of the El Capitan installer. Download the installer from the Mac App Store. Once the download is complete, the installer will start automatically. When it does, quit the installer.

If you allow the installer to perform the installation, the installer will delete itself at the end of the process. We need the installer program to help us create a bootable installer, so it's important that you not let the installer run.

The El Capitan installer is downloaded to the /Applications folder, with the file name Install OS X El Capitan. If you have already installed El Capitan and wish to now create a bootable installer, you can force the Mac App Store to re-download the installer.

You will also need a 16 GB or larger USB flash drive. These instructions will also work for other suitable bootable devices, including an external drive or internal drive, but we'll assume you're using a USB flash drive.

Finally, you will need a Mac that meets the OS X El Capitan minimum requirements.

Creating the bootable OS X El Capitan installer will erase the USB flash drive you're using. Before you proceed, make sure you have a backup of the flash drive's contents or that you don’t care that the data will be erased.

Use Terminal to Create the El Capitan Bootable USB Installer

  1. Connect the USB flash drive to your Mac.

  2. Give the flash drive an appropriate name. You can do this by double-clicking the device’s name on the desktop and then typing a new name. We suggest calling the drive elcapitaninstaller, but you can use any name you'd like, provided there are no spaces or special characters. If you do select a different name, you'll need to modify the Terminal command we outline below with the flash drive name you selected.

  3. Launch Terminal, located in /Applications/Utilities/.

  4. In the Terminal window, enter the following command:

    sudo /Applications/Install\ OS\ X\ El\ Capitan.app/Contents/Resources/createinstallmedia --volume /Volumes/elcapitaninstaller --applicationpath /Applications/Install\ OS\ X\ El\ Capitan.app --nointeraction

    The command is a single line of text, though your web browser may display it displayed as several lines. If you used the drive name suggested above, you can copy and paste the complete line of text.

    Press command+C on your keyboard to copy the command from this page, then paste it into Terminal by pressing command+V.

    Terminal command to create bootable usb flash drive of OS X El Capitan
    Coyote Moon, Inc.
  5. Input your Apple computer password in the password prompt. Press return or enter on your keyboard.

    This command will completely erase the USB flash drive.

  6. The terminal will execute the createinstallmedia command and display the status of the procedure. Erasing and copying the files from the OS X El Capitan installer can take some time, depending on how fast the USB flash drive is.

  7. Once Terminal completes the command, it will display the line Done, and then show the Terminal prompt waiting for a new command. You can now quit Terminal.

The bootable El Capitan installer has been created. You can use this bootable installer to perform any of the supported installation types, including an upgrade install or a clean install. You can also use it as a bootable troubleshooting tool that includes an assortment of apps, including Disk Utility and Terminal.