If your game won't load past the blue screen with the plumbob:
It's probably because you have a post 2013 Mac that is not compatible with the Sims 3 due to the graphics card not being supported. You may be able to get past the launch screen but then your game won't run properly. When you quit the game you may not be able to start again because you get an error message saying "Cannot start the process when the game is running. Please quit the game and try again”. This error message also seems related to the graphics card issues.
The list of Macs affected:
MacBook:
Early 2015, model identifier MacBook8,1, Intel HD 5300
13" MacBook Pros:
Late 2013, model identifier MacBookPro11,1, Intel Iris 5100
Mid 2014, model identifier MacBookPro11,1, Intel Iris 5100
Early 2015 model identifier MacBookPro12,1, Intel Iris 6100
15"MacBook Pros:
Late 2013, model identifier MacBookPro11,2 (2.0Ghz Intel Core i7 only), Intel Iris 5200
Mid 2014, model identifier MacBookPro11,2 (2.2Ghz Intel Core i7 only), Intel Iris 5200
Mid 2015, model identifier MacBookPro11,4, Intel Iris Pro 5200
Mid 2015, model identifier MacBookPro11,5, Intel Iris Pro 5200 & AMD Radeon R9 M370X
MacBook Airs:
Early 2015 11", model identifier MacBookAir7,1, Intel HD 6000
Early 2015 13", model identifier MacBookAir7,2, Intel HD 6000
iMacs:
Late 2013 21", model identifier iMac14,1, Intel Iris Pro 5200
Late 2015 21", model identifier iMac16,1, Intel HD 6000
Late 2015 21", model identifier iMac16,1, Intel Iris Pro 6200
Late 2015 21", model identifier iMac16,2, Intel Iris Pro 6200
This list is not exhaustive. Please bear in mind I am reliant on Mac Simmers like you to post with your Mac's specs if your game is not working due to this issue. To find out your exact model Mac click on the Apple logo, top left of your desktop then select About This Mac. In the window that appears click on System Report. Your model identifier will be in the next pop up window on the right hand side.
There is a workaround you can try which involves editing a couple of game files. For a step by step guide please read my instructions here - http://bluebellflora.com/fix-for-incompatible-graphics-for-the-sims-3-on-mac/ Some people are reporting that their game works if they only have the base game installed, others are managing to play with a couple of Expansion Packs.
I will move any threads I see about this issue to this one so we can consolidate all the information in one place.
And if you try the workaround..... Good luck! 