Loosing all your work

My entire 3DS max file for the fable animation will no longer open. Five minutes after using it previously, then loading it back up again it brings up a file error and wont open it any longer. So wise words to other animators on this course, duplicate your file on your computer, or save it externally. Or you may have to start all over again from the beginning, at week 8 like me.

This is me;