Can't reopen the game on Mac.

I just downloaded the game onto my laptop which happens to be a Mac running El Capitan, when I downloaded the game I saw that the client had updated, but apart from this everything was fine. I played a game then logged off and closed the client. Now it won't reopen, I've looked for solutions but they're all for Windows. Ive redownloaded the game and it worked but when I closed the client again that same thing occurred. I can't keep reinstalling the game very time I want to play. Is there any solutions? Thanks.