I just created and asembly of 3 parts. They were all there when I saved it. When i went back in to re-open it one part is missing. It says it can not locate the part, which the link is correct. When I go and try to open the part from the Assembly tree it comes up blank. But if i exit out of everything and just open the part it's self it works.
I even deleted the assembly and created a new one and also had someone else open up the missing part on their computer.