rraum

I'm sorry that I'm not able to give an answer to this, but I just wanted to say I'm having this exact same problem. I really, really hope there's someone who knows why this is happening. On the activity monitor, "LauncherMain" hang at about 0.2% CPU usage and does not do a thing except display the splash logo of the blue circle wrench thing. I'm not really sure what's up or what's going on, but it could be my fault. Wait! I just found the solution. Try uninstalling Java version 9 (which apparently doesn't work that well with minecraft things) and installing Java version 8 instead!! Here's a link to the page where I got the version 8 download: https://java.com/en/download/manual.jsp