This may have already been answered but I've been away for a while. Loaded Mezzmo, and version 2.1.11 wanted to be installed. Installed. Now all my smart playlists are empty! It seems that if the criteria uses the "is" something, the list is empty. That is, Album is something, list is empty. When Album "contains" something or Album "starts with" something, it's fine. Something is messing up the "is" qualifier.