I'm trying to do a clean install following the apple instructions here under erase your drive: https://support.apple.com/en-us/HT204904 After erasing, when I attempt to install the dialog says "This is not a supported method of installing the operating system. Please run Install OS X El Capitan.app that you downloaded from the App Store. Not sure how to get to that app or what I did wrong if anything. My bootable drive is an SSD if that makes any difference. This is on a 2011 iMac 27 that was recently upgraded to El Cap.