How to go back to Yosemite OS X from El Capitan OS X, How to revert back to Yosemite from El Capitan.Macbook pro, iMac, macbook air, macbook, macbook retina display, macbook retina display 2, mac pro, iMac retina 5k display , mac mini,apple laptop. iMac 27 inch , iMac 21 inch, Macbook 15 inch, Macbook 13 inch.