Hi Michael,

FWIW, I've been using MoI for hours at a time on Mac OS 10.10 and have not seen problems as defined in #1. In fact I've left it open over the weekend and resumed on a Monday and I've been rather surprised on the overall robustness of the app as compared to other 3D apps I'm used to (Lightwave Modeler and SketchUp to name two). I might suggest the OP to update their Mac. I believe the updates are free.