I can open the attached file which was stable the last time it was saved (~3months ago) and it will open just fine.  I can even do a rebuild and everything is fine.  But if I try to edit a feature (it seem almost any feature), the model crashes.  In particular I am trying to edit the size of the holes in the machining folder feature "Cut-Extrude21".

FYI this is a '15 file.