Shows all the files that are not matched to either a MusicBrainz or Discogs release in the right hand side using a file tree view. Songs that were matched to a MusicBrainz song but not release are listed here.
To be considered matched they need to have matched a release not just a MusicBrainz song. If you have songs that were previously matched to MusicBrainz or Discogs but were not matched during this last run of Fix Songs they will still be listed in the Not matched section because this section is designed to show those songs that could not be identified during the last run of Fix Songs