First of all, if you are new to either Macs or Sims 4 and play on a Mac, please read this thread. It's always best to research what problems you can have or others have had and how to avoid them or solve them yourself.
The Wonderful BlueBellFlora has a comprehensive guide to all things Mac for the Sims 4 game. I recommend reading it before posting here. She gives step by step instructions on how to solve most problems that affect those of us who play on the Mac OS. (All computers are PC's which is shorthand for "Personal Computer"). Here is a link to her blog.
This is by no means the only Mac Help Section dedicated to playing on a Mac. Many of us still play Sims 3 and there is a specific Mac Help Section for Sims 3 only. Beware that newer Macs have problems with the playing Sims 3 especially MacBooks. This section is found further down on the Forums page under "Legacy Titles". Here is the direct link for this section. http://forums.thesims.com/en_US/categories/mac-discussions
And lastly, Origin does not track the hours you've played Sims 4 on a Mac. This is a known issue, will probably never be fixed and does not affect how the game runs or plays. What matters is if you having problems getting the game to run and play properly.
Speaking of Origin, turn off Automatic Updates in the Options section. Why you ask? Whenever the game is patched, Modders and CC makers may have to update their content as EA/Maxis have corrected or changed the way the game plays. These folks will need to update how their mods work or you will get game errors and the game will not start or play properly. Keep note of where you download your mods/CC from and check these sites for updates before you update and patch your game. It will save you hours of headaches later.
Another tip to pass on concerns CC and Mods. Unfortunately there is no "program" that will allow Mac Users to sort through Bad Content. You will have to remove the Mods and CC from your game. So it is best to move your Sims 4 folder to your Desktop (Documents > Electronic Arts > Sims 4). DO NOT DELETE IT! Start up your game to allow a new folder to generate and then add back a few pieces of CC at a time to determine which ones are bad. I color code mine so that I can find the bad CC more easily.
So Mac Simmers, here is your one stop shopping guide to all things Mac, Sims 4 and how to solve the most common problems found. Enjoy!
**Edited to add more information**
Second Star to the Right and Straight on 'til Morning.