Barrie Tingle, Live Producer at Maxis, has confirmed via Twitter that they are looking into the issues that are plaguing Sims 3 Mac users. Many users have reported that their game has become unplayable, so hopefully EA releases a patch for this soon.
@BluebellFlora1 @TheLadyHades @TheSimCommunity Yep. We are looking into the TS3 Mac issues. Nothing else to share on it yet, though.
— Barrie Tingle (@barrietingle) November 16, 2016