Updated
September 21, 2016.
OS X El Capitan, the latest version of OS X as of the summer of 2015, is available from the Mac App Store as a free download. Like previous versions of OS X, El Capitan has the annoying habit of automatically starting the installation process once the download is complete.
This would be fine if all you wanted to do was quickly install El Capitan as an upgrade install over your existing version of OS X.
But even if this is your goal, it's not too likely that you're actually ready to start the install process. After all, there's quite a bit of housekeeping to be done before you commit to installing OS X El Capitan: that includes having a recent backup of your data, and making a bootable OS X El Capitan installer on a USB flash drive.
Having a bootable installer for OS X El Capitan is a good idea, even if your plan is just to perform an upgrade install, which technically doesn’t need to be done from a separate boot device. But having your own copy of El Capitan on a separate device ensures that you'll always be able to install or reinstall it, or perform basic Mac troubleshooting tasks, even if you have no connection to the Internet or access to the Mac App Store, should you need to re-download El Capitan.
How to Create the Bootable Installer for OS X El Capitan
There are two methods of creating the bootable installer; one involves using Disk Utility, the Finder, hidden files, and a great deal of effort and time.
If you wish to use this method, you can follow the guide How to Make a Bootable Copy USB Flash Drive of the OS X Yosemite Installer, and no, that's not a typo. The older process outlined in the Yosemite document will work for El Capitan; you need only be aware of file name changes, such as El Capitan instead of Yosemite in the instructions.
There's also a second method, and it's the method I prefer, because it's less involved, has few places where things can go wrong, and only involves using a single app: Terminal.
What You Need
First, you'll need a copy of the OS X El Capitan installer, which is available from the Mac App Store. Until the official release of OS X El Capitan on September 30th, 2015, there will be multiple public beta versions available throughout the summer in the store. This guide will be updated as needed for each version once they become available.
Next, download the installer from the Mac App Store. Once the download is complete, the installer will start automatically. When it does, be sure to quit the installer. If you allow the installer to actually perform an 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 don’t let the installer run.
If you have already installed OS X El Capitan, and wish to now create a bootable installer, you can force the Mac App Store to re-download the installer.
- The El Capitan installer is downloaded to the /Applications folder, with the file name Install OS X El Capitan.
- A 16 GB or larger USB flash drive. These instructions will also work for other suitable bootable devices. I’m going to assume that you're using a USB flash drive, but any bootable device will work, including an external drive or internal drive.
- A Mac that meets the OS X El Capitan Minimum Requirements.
Have everything you need? Then let's get going by moving on to Page 2.
Published: 6/15/2015
Updated: 4/26/2016