When I tried to create a new account with an older version like 1.0, it launched the game properly, but then instead of a Mojang screen, a black screen appeared. I tried to winden the window. The Mojang logo finally appeared...upside down with really low FPS! And so with the main menu. It happened too when I tried to create an account with the 1.1 version. Maybe it's because I"m playing on a Mac...or not.