I have a mid 2012 Macbook Air on Yosemite that I want to do a Fresh install of El Capitan. I created an USB flash drive with terminal and an El Capitan installer. Ive already used it on a late 2008 Pro and installed El Cap on it so I know it works fine. However with the Air I put the USB in and restart holding the option key and choose the Installer then it boots directly into the El Capitan installer. I don't get the option for the OSX Utilites window with Disk Utility option to reformat the drive. I went under the Apple in the finder and it doesn't open. I can click back on the installer and get the language options. I click Continue it begins the installer. Any reason why I can't get to the Disk Utility option to wipe the drive?