Thanks for replying.

@Michael
I'll see if I can email you the 3dm file.
The objects are not hidden, they're gone both from the screen and the object menu.

@Bemfarmer
I'm not trying to recover the objs, I have them already. The projects are open and closed in 3dm.
I only mentioned the obj export to illustrate that everything was in working order before closing the project.

thanks again-