I have finished an injection mold, and I saved the assembly file as a step file in a folder accessible on the shop floor. I needed to tweak some features, so I went back to open my assembly file to do additional work, and most of it is gone. I've been thinking about this all weekend, and have come up with nothing. I might be able to provide screen shots later. The files in question are there in the feature tree but greyed out, and Solidworks can't find them.