Rekordbox not opening

I recently updated to Rekordbox 5.7 on my iMac (27-inch, Late 2013) and when the install finished the software doesn't open. The dot is below the icon in the dock but no window appears at all. And it won't quit, I have to force quit to close the app. I tried reinstalling it but the same thing happened. I installed from the 5.6 installer but the issue is happening again. 

Has anyone else experienced this? Or solved it?