WoW not opening

Yo!
Sorry if I seem a bit dim, but I can't seem to find any other topics on other ppl not being able to open WoW.
So psyched for tomorrow and now there's only one problem: WoW won't open. I have downloaded the mac osx client and got the realmlist set, but only thing to appear is a black screen, when i open the game.
I have a mac Yosemite v. 10.10.2.
Anybody got an idea?
Peace
Sorry if I seem a bit dim, but I can't seem to find any other topics on other ppl not being able to open WoW.
So psyched for tomorrow and now there's only one problem: WoW won't open. I have downloaded the mac osx client and got the realmlist set, but only thing to appear is a black screen, when i open the game.
I have a mac Yosemite v. 10.10.2.
Anybody got an idea?
Peace