We've seen some intermittent issues with the Mac version of MatterControl, and while we've got a new build in the works it's not reliable enough for release just yet. As in my post on this topic on the old forum (4th from the top), you can copy the terminal text and send it to us so we can debug. If you have another operating system you can use (Windows) to use in the meantime that will probably be the best way to get you up and running the quickest.