Problems starting up Sims 3 (MAC)

[redanc19]

Today I bought and downloaded The SIms 3. The whole installation went well until I wanted to start the game. The launcher pops up and I click the "Play" button and the screen shows the big green diamond, but the game never starts. I dont know what to do. I've tried to uninstall the game, but the mac doesnt seem to be able to uninstall the game. What do I do?

My mac is a brand new 2015-generation MacBook Air.