I'm trying to upgrade from Mountain Lion to El Capitan on my Mac Mini. I go to the app store while logged into my Apple ID, and try to download the free upgrade, and I'm told to log into the account I used to purchase it. But, it's free, and I'm already logged into my Apple ID, and there's nowhere in that window to log into anything, and I have no idea what account they are talking about, so I guess I've hit a brick wall and can't get El Capitan. Anyone know a way around this? My machine is a late 2012 Mac Mini Processor 2.5 GHz Intel Core i5 Memory 8 GB 1600 MHz DDR3 Graphics Intel HD Graphics 4000 768 MB Software OS X 10.8.5 (12F45) At one time I was able to get a live chat with Apple and they told me I could upgrade straight to El Capitan from Mountain Lion and all would be well, but I can't get that chat anymore or find any way to get it back or open a new one. I don't understand how to proceed from here.