Twice now I have experienced a situation where my .skp file is no longer functional. I am unable to select entities without a crossing window, orbit is no longer functional, textures are lost and becomes a mixture of wireframe and material view. I didn’t get a bug splat and re-opening the file or re-starting the application makes no difference. Other versions open fine.
I noticed the same thing. Camera was located strangely. Switching to Perspective fixed it.
Do your modeling with the Camera set to Perspective and save Parallel Projection for specific scenes. That’ll prevent you from getting the camera placed badly.