Anyone who is experiencing the infamous “hang-on-project-close” problem in Cubase, I wrote a step by step instruction how to find out which of your many many plugins 
is the culprit. It is not for the faint of heart as it involves installing and using a debugger (you cannot break anything though, no worries)
(I know that there is a newer, easier to use version of WinDBG now, but I haven’t used it, so I cannot give instructions.)
I also posted my findings on why this only happens in Cubase and not in other DAWs like Reaper over in another thread.
I would really like to hear from SB whether I am on the right track with that.