OpenStudio bug "an unhandled exception has occurred - bad cast"
I encountered a bug in OpenStudio 2.8.0: it randomly shuts itself down and sometimes gives the above notice. I've installed the programme (version 2.9.1) on another laptop and the same thing happened; it only manages to stay open 1 minute max, then it crashes.
Does this happen when you open a particular OSM file or try to do a specific action? If so, the development team should be able to figure out what the problem is pretty quickly if you can provide them an OSM file or more detail.