I'm using Solidworks 2015 and have the following problem:

I have an large assembly that I'm making a drawing for (standard views).  I have been creating drawings for this assembly for about 6-8 months now (different configurations), but suddenly have an issue in the last drawing - the edge lines of all items do not show on the drawing.  To clarify, the outer edge is shown, but all feature details inside of the outer edge are not shown - the parts appear to be blank.  I've tried reviewing the drawing options and have limited success doing the following: 

     - Under the Drawing Property Manager, choose a different display style, like "hidden lines visible".  When I change back to "Hidden lines removed", the parts actually show the correct features.  However, as soon as I save the assembly the features disappear again.

I have drawings of the same assembly that I created earlier that still appear to be fine.  Any ideas or thoughts on how to make this work would be greatly appreciated.  Thanks!