Hello,
I am suffering this same problem, last night printed off a drawing (the desktop I was working on was sized to A3 to match the required print out) then saved and closed the drawing, remembered I needed a 2nd copy so attempted to re open the file without success.
When I clicked properties it showed file type as 'file' and the size as '804kb', I cant save it to a different format as it wont open, tried renaming it with extensions like .jpeg, .png etc and opening in other programs but the cant open it either.
Ugg
Help
R.