I'm seeing the MOUSE engine (MOUSE Simulation Launcher) lockup during it's startup phase without an error message. It occurs when the status bar text is "Initiating Simulation Launcher". One time I saw this error before on Mike Urban 2012, I eventually traced it to weir and a valve element with the same MUID and changing one MUID fixed it.
Anyone else seen other causes? That's not the issue this time, so I'm trying to debug why I'm getting the error.