I picked The Beatles because it's "hard", but also because it's the most likely candidate to have all of the metadata populated (including instruments). And it'

I picked The Beatles because it's "hard", but also because it's the most likely candidate to have all of the metadata populated (including instruments). And it's a perfect example of why a gigantic database that tries too hard to please the 'train spotters' with catalog numbers and barcodes, is not suitable for someone who has the album version of a song and just wants to tag it. What normal person knows/cares what a release group is? Edit: "You probably want to find a release of that release group that closely matches your files". And this is why you can't just point it at your library and let it go. You need to shepherd it at every turn or it'll screw things up. I've used countless auto-taggers over the years (all of which pull from MusicBrainz) and I've never had decent results. These days I tag manually. Most of it's already done, so I just have to handle the new stuff, and sometimes update old stuff (add instruments that 'stand out', update ratings etc).