[josephzitt]

In looking at my Artists list, I see odd alphanumeric artist names, such as (hoping I type this right, since I don't know of a way to copy and paste it from Kodi into here):
28dc2e12-ee49-429a-9ca4-386e26c27c4a
They seem to consistently be the same length, with the same numbers of characters between the dashes.
They remain the same even after removing and rescanning the media source.

When I look at the tracks with other tools, the Artist, Album Artist, etc tags look like the appropriate normal names.

Any idea why this is happening and how to change it?

[jjd-uk]

Those are Musicbrainz ID's and if you're seeing those in the GUI then there's some inconsistency in the tagging, you need to use something like mp3tag to look at the extended tags.

[josephzitt]

Looking at them since I posted this, I notice that these are almost entirely classical releases. I think they are mostly distributed by Naxos (though not necessarily on the Naxos label). No idea if this tells us anythingn

[jjd-uk]

Your example would point to you having tracks with the MBID for Nash Ensemble see https://musicbrainz.org/artist/28dc2e12-...6e26c27c4a

So something with the Artist or Artists tags does not agrees the the MBID's that have been added to the tracks.

[DaveBlake]

Classical releases => multiple album artists. You need to ensure that you have an ALBUMARTISTS tag to provide names to match with the album artist mbid tag value and allow Kodi to pair artist name to mbid. Plenty of posts from me about that on this forum.

Easy way is to tag using Picard, and set script
$setmulti(albumartists,%_albumartists%)
so this is done automatically. Unfortunately unlike the ARTISTS tag this is not done by default.

[jjd-uk]

Looking back Dave described issue in more detail here https://forum.kodi.tv/showthread.php?tid=333668

[josephzitt]

So if I change the Album Artist to something different from what it picks up from MusicBrainz, Kodi looks at the MusicBrainz value, overriding what I put in? Some of the values in MusicBrainz are quite odd. Is there a way to specific that Kodi should use the values that I expressly put in myself?

For example, the album in question was this: https://musicbrainz.org/release-group/82...5952437cd8

MusicBrainz lists for it "Release group by Julian Anderson; Nash Ensemble, Martyn Brabbins"

I had changed the Album Artist to just "Julian Anderson", since I prefer to have his albums grouped simply together, rather than splattered into different listings by each different combination of artists playing his music. How can I get Kodi to respect that, or at least use a human-readable value?

[josephzitt]

Looking back Dave described issue in more detail here https://forum.kodi.tv/showthread.php?tid=333668

I get a bit lost reading that. It seems to get deep into the weeds on Picard scripting. I use Picard (as well as MP3Tag) but don't quite follow what's going on. We're in a maze of tags, all named almost imperceptably different, with squiggly bits of code handling them :-) I have about 2 TB of MP3s, collected and tagged over decades, so it's daunting.

[jjd-uk]

You probably have that album listed as desired under Julian Anderson, and also again under 28dc2e12-ee49-429a-9ca4-386e26c27c4a and you probably also have a 6a2b7c54-e605-42da-ae82-e605bce614f1 for Martyn Brabbins which again contains the album? that because there will be MBID's present that don't match up to the AlbumArtists tag, so you just need to delete the MBID's for Nash Ensemble and Martyn Brabbins so you have the single MBID for Julian Anderson.

EDIT: @jjd-uk  sorry stepping in here, but what you say doesn't make sense to me. And deleting mbids is NOT the answer!! Matching pairs of enties is always the way to go

[DaveBlake]

We're in a maze of tags, all named almost imperceptably different, with squiggly bits of code handling them :-) I have about 2 TB of MP3s, collected and tagged over decades, so it's daunting. 

Focus on those with mbids as names... they will (mostly) be from albums with more than one album artist, which will mostly be the classical stuff with composer, conductor and orchestra as the album artist (but you may have the odd other collaboration).

Add the scripting line I mentioned to Picard settings, and retag just those releases with multiple albumartists (a fraction of your 2TB).

The tagging isn't that complex:
ALBUMARTIST tag can be a string of many artist names and punctuation isn't enough to separate them e.g. "Earth, Wind and Fire" is one artist "Arvo Pärt; Benjamin Hudson, Sebastian Klinger, Jürgen Kruse" is 4 artists.
ALBUMARTISTS (note the "S") is clearly separated artist names e.g. "Earth, Wind and Fire", "Arvo Pärt / Benjamin Hudson / Sebastian Klinger / Jürgen Kruse" or using mutiframe value.
MUSICBRAINZ_ALBUMARTIST_ID the mbid values to use for each artist

You need to add ALBUMARTISTS (note the S) tags to your albums with multiple album artists.

Modify your Picard settings as I suggest and it will do it for you.