Great Graphics but Keeps Freezing

This is the first game I bought for my new MacBook PRO. Hardware should not be an issue (2.5 i7, 16GB Ram, Intel Iris Pro 1536 MB and 512 GB SSD), but the game keeps freezing after I have completed/won a stage. It will not allow me to progress through the game. I gave it a 3 Stars because the graphics and car physics are incredible. I hope they can fix it because it could be a Great Game!

akaSigfreak about DiRT 3 Complete Edition