If you have blu rays set up in BDMV folders and wish to use My Movies, it will not be happening in 12's present state. i finally got the definitive answer on My Movies forum. They found a workaround to send a BDMV as a command line in 11 but this cannot be done in 12.
Michael if you read this and while i hold no expectations, if this could be considered an issue it would be appreciated by me and i am sure many other customers who use My Movies.