It was 2009 when Apple last released a new operating system on physical media. Things have proceeded remarkably smoothly since version 10.7 switched to download-only installers, but there are still good reasons to want an old, reliable USB stick. For instance, if you find yourself doing multiple installs, a USB drive may be faster than multiple downloads (especially if you use a USB 3.0 drive). Or maybe you need a recovery disk for older Macs that don't support the Internet Recovery feature. Whatever the reason, you're in luck, because it's not hard to make one.
As with last year, there are two ways to get it done. There's the super easy way with the graphical user interface and the only slightly less easy way that requires some light Terminal use. Here's what you need to get started.
Install Disk Creator will automatically detect your 'OS X' installer file. If you have an old installer file from El Capitan or Yosemite installed, you might have to choose 'Select the OS X installer' button, then navigate to your Applications folder and select 'Install macOS Sierra.' Install El Capitan from Scratch. Backup if possible before continuing. Restart the computer. Immediately after the chime hold down the Command and R keys until the Apple logo appears. When the Utility Menu appears: Select Disk Utility from the Utility Menu and click on Continue button. New Disk Utility is here to stay, this tutorial explains all the new features found in macOS Sierra. Not sure I understand the above question but it would make sense that the El Capitan recovery command will boot you into El Capitan recovery 'disk'. There is no way to 'revert' this. If you would like to format an earlier version of OS X you will have to do it from a bootable USB drive-perhaps one that you made in the past.
Once you've obtained all of the necessary materials, connect the USB drive to your Mac and run the Diskmaker X app. The app will offer to make installers for OS X 10.9, 10.10, and 10.11, and it should run on OS X versions all the way back to 10.7—support for 10.6 was dropped in the most recent release.
AdvertisementDiskmaker X has actually been around since the days of OS X 10.7 (it was previously known as Lion Diskmaker), and it's still the easiest GUI-based way to go without intimidating newbies. If you're comfortable with the command line, it's still possible to create a disk manually using a Terminal command, which we'll cover momentarily.
Select OS X 10.11 in Diskmaker X, and the app should automatically find the copy you've downloaded to your Applications folder. It will then ask you where you want to copy the files—click 'An 8GB USB thumb drive' if you have a single drive to use or 'Another kind of disk' to use a partition on a larger drive or some other kind of external drive. Choose your disk (or partition) from the list that appears, verify that you'd like to have the disk (or partition) erased, and then wait for the files to copy over. The process is outlined in screenshots above.
If you don't want to use Diskmaker X, Apple has actually included a terminal command that can create an install disk for you. Assuming that you have the OS X El Capitan installer in your Applications folder and you have a Mac OS X Extended (Journaled)-formatted USB drive named 'Untitled' mounted on the system, you can create an El Capitan install drive by typing the following command into the Terminal.
sudo /Applications/Install OS X El Capitan.app/Contents/Resources/createinstallmedia --volume /Volumes/Untitled --applicationpath /Applications/Install OS X El Capitan.app --nointeraction
The command will erase the disk and copy the install files over. Give it some time, and your volume will soon be loaded up with not just the OS X installer but also an external recovery partition that may come in handy if your hard drive dies and you're away from an Internet connection.
Whichever method you use, you should be able to boot from your new USB drive either by changing the default Startup Disk in System Preferences or by holding down the Option key at boot and selecting the drive. Once booted, you'll be able to install or upgrade El Capitan as you normally would.