I am working through in house solutions mill level 1 and when i open my saved drawings there is nothing. In the file preview that comes up on the lower left hand corner of my documents menu I can visually see the drawing, but once the file is opened there is nothing there. I have tried zoom to fit, and unhide entities with no results. Unhide entities brings up "Hiding error. either the displaylist is off, or there are no entities on screen." I am extremely green to mastercam and any help is appreciated.