Renwu Zhang

Only screen is whiter than my 2011 Mac. The operating system is terrible compared with the old Snow Leopard. Just a few examples: (a) in iTune, you can never find a radio station, all popups are asking you to buy something and ugly pictures. (b) in preview, when you open many picture, it always tells you too many files and runs slowly. Plus, before, in Snow Leopard, it can make the low...