Import the attached project and open the scene menu.unity. It has continuous baking enabled, so let the baking process run. I let it run over night and from the log file (when I came to work in the morning) I could see nothing happened for 9 hours. The Editor shows the progress bar update status stuck on 6/16 Bake Visibility | 22 jobs.

I attached a debugger to the running JobProcess.exe and here's the stacktrace of what it was doing: http://i.imgur.com/LlmiR2a.png

I tried closing Unity after that and it crashed, without being able to output a stacktrace. This bug report does have a stacktrace in the Editor.log file from the crash the user experienced initially.