If you need to install El Capitan on multiple Macs, using a bootable installer drive is faster and more convenient than downloading or copying the entire installer to each computer. In other words, you no longer have the same safety net or convenience.īecause of this, I recommend creating your own bootable El Capitan (OS X 10.11) installer drive on an external hard drive or USB thumb drive. But to install or reinstall a recent version of OS X, you must either download a non-bootable installer from the Mac App Store or (via OS X’s invisible, bootable recovery partition) download 6GB of installer data from Apple’s servers during the installation process. When OS X shipped on a DVD a good number of years ago, you always had the convenience of a bootable installer-an OS X installer that could be used to boot your Mac if its own drive was having problems.
