@Jennym6 I understand the issue, and it's an unfortunate result of the Advanced Rendering option being disabled. When it's enabled, there's a separate issue, namely that whenever the snow depth is greater than zero, roads show through walls of any rendered building that isn't a rabbithole. But that's beside the point.
When you enable Advanced Rendering, are you quitting to desktop after changing the setting and before trying to load a save? Does it help if you delete options.ini, in Documents > Electronic Arts > The Sims 3, and try again? If the game still crashes, please post the full specs of your computer: everything under About This Mac except for the serial number.