I’m on N4.3 but I never get a response when I post on the N4 page. I’m hoping for better results here. I’m working on a classical chamber peice for string quartet, 2 flutes, oboe & clairnet. I’m using VSL and Halion for all of the parts. I finished the cell edits on my cello line, SAVED and closed the file on Saturady night. When I returned to edit the other 3string lines this morning, I got an error message saying that none of my MIDI tracks were mapped to anything! When I looked ant the instrument windows NONE OF MY INSTRUMENTS WERE THERE. 
I checked my last version saved (just before the cello edits) and all the instruments were there. With no other choice, I re-loaded the instruments. But one patch, 'EXPRESSIVE FLUTE" WAS NOW MISSING FROM HALION. So now I’m making do with the regular flute patch.
I have had numerous problems with Halion loading. The instrument shell loads without ANY patches. The instrument loads with the instrument patches but it won’t access them. Instruments just seem to come and go at will! This is really annoying. Why didn’t the instruments stay put after the last save? Has anybody else had thi kind of problem, if so, how did you solve it?