Twonky database rebuild gets stuck on 1 file

Twonky server was working fine when suddenly it stopped working.  Database rebuild gets stuck on a particular film (Iron man).  If I move the film and try rebuilding database again then Twonky gets stuck on another film.  It seems I can’t finish updating the database.  Also now it seems everytime I add another file I have to rebuild the database again!  Nightmare!!  I tried updating to WD DLNA server but that seems no good as it can’t play .MKV files (which I have a lot of).  Please help.  I’m at the end of my tether!!  

Try resetting the device to factory settings or restarting the Twonky server.

How to access the Twonky Media Server on a WD My Cloud, EX2, EX4, My Book Live, My Book World (White Light) or WD ShareSpace

I’ve tried both but the same thing keeps happening.  

This is not a solution, but just to tell you that I have exactly same program. It’s really irritating !!