I've been using MM for ages, and rarely end up here as it just works. However, I'm foxed with this one.
I've just built a new Windows 10 PC (Enterprise X64) and migrated everything across to it, including my Lifetime Gold license of MM 4.1.11.1783. Once I'd followed the guides and run the scripts to locate all the moved files, everything works fine, except that now all the tracks in my library are showing and playing twice.
It doesn't matter whether I look by location, artist, genre etc. - everything shows twice. The only things that are right are my playlists.
Screenshot:

I have re-scanned the library, and have startup and auto-scanning on. Any thoughts as to what I can do next?
Noel Weston