I encountered this error when trying to open a part in Solidworks 2013 x64. The part has split bodies that I used to generate an assembly. The assembly opens fine and the parts behave as normal. I can open the individual parts. However, I can't edit the parts in context. I either get this error or Solidworks crashes entirely.

This first occurred when I had both the assembly and the part open. I accidentally closed the part and got the error when I tried to reopen it (in the same session).

I've restarted solidworks and the computer, moved the file to a different location, and run the "cleanup" from Solidworks Rx. Still nothing works. Is there a way to recover this file (or at least the sketches that generated the parts) since the individual parts seem intact?  Thanks!