Re: Can I play/access the Sims 4 on both Mac and PC?

@dandylittlelion  You can absolutely run Sims 4 on both your Mac and your Windows PC.  I have the game installed four times covering both OSs, and none of the installs affect the others.

It's always a good idea to back up your saves.  Playing on multiple systems shouldn't be a risk factor, but you never know when you'll run into computer trouble.  A reasonably-sized external drive or USB stick is cheap and can hold a giant pile of saves while giving you peace of mind.