Download the El Capitan Installer
Download the El Capitan installer from the Apple website. It is no longer available in the App Store. Once the download is complete, the installer starts automatically. When it does, quit the installer. You need a copy of the El Capitan installer to make a bootable USB. The El Capitan installer is downloaded to the /Applications folder, with the file name “Install OS X El Capitan.” If you’ve installed El Capitan and want to create a bootable installer, re-download the installer from Apple.
Use Terminal to Create the El Capitan Bootable USB Installer
Follow these steps to create a bootable USB installer of El Capitan in Terminal. The bootable El Capitan installer has been created on the flash drive. 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. 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 as several lines. If you used the drive name suggested above, you can copy and paste the complete line of text.
Why Make a Bootable USB Installer
A bootable installer for OS X 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 the OS X. It also helps in performing basic troubleshooting tasks, even if you have no connection to the internet or access to the Mac App Store.
What You Need
A Mac that meets the OS X El Capitan minimum requirements. A 16 GB or larger USB flash drive. The El Capitan installer file downloaded from Apple but prevented from completing the installation.
