Can anyone explain what I’m doing wrong?
I have the MP3 album The Rolling Stones - Golden Rock Classics vol. 2
Picard doesn’t find just one Gimme Shelter tag.
But on June 22, 2023, I entered the data of this song into the database.
I have more such cases.
What you have is CD2 of a double album and not a release in its own right (or at least not in the Musicbrainz database).
Copy and paste the MBID from that URL into Picard’s Album search box at the top and it will load the metadata for it.
And then move the Gimme file from the left to the right panel?
I did that a day ago.
Now I cleared the tags for this disc and ran Scan in Picard.
This song is still not recognized.
Have you submitted the audio fingerprints after manually matching it? Scan does audio fingerprinting using AcoustId. If that does not give results AcoustId likely does not know about the song, and unless someone submits the fingerprints that won’t change.
A bit strange for a popular song like Gimme Shelter, but maybe it is some specific recording. In any way if the recording has no linked fingerprints (Recording “Gimme Shelter” by The Rolling Stones - Fingerprints - MusicBrainz) scan can’t find it.
See also Submitting Acoustic Fingerprints — MusicBrainz Picard v2.10 documentation
As a general note for cases like yours and especially for compilations I’d recommend to use cluster + lookup over scan unless lookup does not give results.
It turned out to be the song “Salt of Earth”. The file names were swapped. I corrected it.
Then
I added the album directory to Picard,
I pasted the MBID f47112b6-b1d5-4f6b-a177-b681a071dfdb
I moved the song Salt from the left to the right panel.
However, the fingerprint is not available and the song lengths on the second album are missing.
You need to run “scan” or “generate acoustid fingerprints” on the file first. “generate acoustid fingerprint” only does the fingerprint calculation (which is enough for submission), while “scan” also does the online lookup stuff. But after both the fingerprint will be available.
For generate fingerprints either side is fine. “Scan” can only be done on the left (and has the side effect to also finding results if there are some).
I can’t say for sure. But usually if everything is working fine only a couple of minutes maybe. Recording “Salt of the Earth” by The Rolling Stones - Fingerprints - MusicBrainz already shows a linked AcoustId, that’s probably the one you submitted.
But if AcoustId was busy and there was a long submission queue or if there was some technical issue it also took longer.
@outsidecontext however, this is not the end yet. 
I have this choice in Picard:
Click Generate fingerprint in the left panel and submit it
Find the MBID of the album, move the file from the left panel to the right one, click Generate and submit it
What I mean is that if manual matching of a file to an album is required, the Generate function does not need to be available in the left Picard panel.
My question in short:
If there are any unclustered files, do you always have to manually search for the album or is it enough to somehow recalculate the fingerprint?
The generate fingerprint function is really just there to calculate the fingerprint without doing anything else. You can do it on the left panel before matching the files to tracks or afterwards (but you can only submit something once you have matched to a track). Some people also use it to store the fingerprint in the tracks (needs to be explicitly enabled in options) as they use it later with some other tool.
The fingerprint alone does not help you much, it only becomes useful once you can look it up on AcoustID to get the proper recording on MB. If AcoustID does not know about the audio yet you won’t be able to look something up. It is as if I play you some song you never heard before and then ask you about how it is called and on which album it appeared. You won’t be able to tell me 
Except for manual matching the other automatic way is metadata lookup. Which in many cases would be preferred over acoustic fingerprinting as it often gives better results (e.g. select the proper release the recording appears on) if existing metadata is reasonable good.
Now I understand you keep removing all tags before doing scan. But we already told you you are making your life harder unnecessarily by doing so
I still have this doubt.
Maybe this will help Picard’s development.
I still consider the Rolling Stones - Golden Rock Classics disc 2 album.
“Gimme Shelter” and “Salt of Earth” are OK.
I’m talking about the song “Stray Cat Blues” from the album “Beggars Banquet”. You can hear the Jagger/Richards duo there, not the Hoss band.
After Scan, this file remains on the left.
If I also press Lookup, it will appear with the Hoss band.
Of course I didn’t accept it.
I moved the song “Stray cat” to the album “Beggars”, submit fingerprint and Save.
My question is this:
now everyone who has this MP3 file “Stray cat” will no longer have to correct it. Will he get the same result as me?
I will try not to clear tags anymore.
Let’s assume I won’t clear tags with Mp3Tag.
After the first full scan and saving, will I be able to add the music directory to Picard from time to time to retrieve the current tags?
Will the release-modified icons appear in the right panel of Picard?
If for that song there had been previously no associated AcoustId fingerprints others should get the result with “Scan” after your submission. They might or might not get the exact same result as you, based on existing metadata. A recording can be on multiple releases, and a fingerprint on AcoustId can be linked to multiple recordings, so Picard has to pick one (which it does by metadata comparison).
Submitting the fingerprint has no effect on the functionality of “Lookup”.
As long as you keep the standard settings Picard will write the recording and release MBID to the tags. If you load files into Picard which already have these MBID tags it will automatically load the matching releases on the right and attach the loaded files to it. That way updating the tags it is just a matter of dragging the files into Picard, maybe check what gets updated and saving again.
Let’s consider the same album:
and the song Stray Cat Blues
I fixed it a few days ago and sent fingerprint.
ID results like this:
b071f9fa-14b0-4217-8e97-eb41da73f598
479ec2d3-d1f1-4dfb-abb7-1ff55c88d37e
b071f9fa-14b0-4217-8e97-eb41da73f598
491be72a-21e8-49a5-af52-a06a5deb4916
f47112b6-b1d5-4f6b-a177-b681a071dfdb
2c29b996-b199-40c8-b665-75d795e75531
For testing purposes, I cleared the tags in this album, loaded the catalog into Picard, clicked Scan.
Stray Cat stayed on the left.
I clicked Lookup and Stray Cat was incorrectly assigned to the band Hoss again.
ID results like this:
b6bfd95d-3401-44e6-8f4b-a9fd8cc50d6d
e8b61cc4-5f17-48ec-83ce-cbe9ad1cb97f
b6bfd95d-3401-44e6-8f4b-a9fd8cc50d6d
7a649e3d-74ae-3464-b2e6-23b793199f0b
20d20667-8865-4efc-abe0-544fa210b27a
0558662d-b453-3e1a-aab1-e3b63406c6ac
You removed all the information and the only info Picard was left with was a track number (8) and title (“Stray Cat Blues”), both of which Picard guessed from the filename, and the file’s duration (4:23). It found you a recording titled “Stray Cat Blues” with a duration of 4:23.
Really, let’s not repeat that discussion again and again. If you remove all the useful information Picard has to deal with what is left.
