Since 2009 Apple has switched to download-only installers for their new operating systems. but there are many reasons to want to use a USB installer, for example a USB drive can be much faster when having to do multiple installs.
What you need to get started:
- a Mac that you have administrator access to.
- an 8GB or larger USB flash drive
- The OS x 10.11 El Capitan installer from the Mac App Store in your applications folder.
- If you want a GUI, you will need the latest version of Diskmaker X app. (version 5)
Once the Diskmaker app is installed in your applications folder you can connect the USB drive to your Mac and run the Diskmaker app.You will need to select the version of OS x you want, (you will be needing El Capitan 10.11) the app should then 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”Choose your disk from the list that appears.select “Erase then create the disk”
You will then need your Administrator login details
Continue to transfer the files
Apple has included a terminal command that creates an install disk for you.
All you need is the OS X El Capitan installer in your applications folder and you have a Mac OS X Extended (Journaled) – formatted USB drive connected to your system. You can create the 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