Well if you are a 3ds max user then you should be used to having a crash once in a while 
It might have to do with updating the project to a newer version. First try to “build” the project.
Also if you are “launching” the game look into the “saved” folder and delete these two directories: “Editor Cooked” and “Staged Builds”.
You can also try to delete the “saved” and “intermediate” folders. They will be recreated.
If all that doesn’t help then create a new project and migrate everything to that new project.