Running El Capitan on two machines without any trouble, so I decided to enrol my wife's machine (different iCloud account/Apple ID). I went to the beta reg page and downloaded the OS X El Capitan Public Beta Access Utility. I ran it - and it immediately comes up with an error, saying it needs OS X 10.11. I have no option but to hit okay, and it just quits. The computer in question is a new Macbook Air, running 10.10.5. Does anyone have an idea on how to get around this? Or should I just sign in with my Apple ID, download the El Capitan GM from the App Store, install it, then try the utility?