game freezes but all my sims can move

Hi Sims team, I've been playing on the Sims on my Mac now for a few months. I've noticed this horrible glitch where my game freezes. My Sims are still moving around, music can still play, but when I go and tap on another sim, the pause button or the speed button, nothing works. I tried saving the game, but it won't save, and it's just on a continuous loading screen. I have to restart my Mac so I can get back into the game. 

This is constantly happening, and this glitch happens unexpectedly. Within 15 minutes, out of the blue, it freezes. I've tried to repair the game, but it's not fixing it.