When I upgraded to Catalina 10.15.7 (iMac) I had no problems using Sonos everything was fine unlike others or so I thought.
I only noticed recently that the daily music library update was pushing out a message that I had too many Playlists and the update could not complete and I should delete some playlists and re-run the update or words to that effect.
Checking in the Music app I only had approx. 70 playlists which should be ok.
Checking my imported playlists in Sonos I noticed 2 playlists called Home Videos & Music - Home Videos contained all my Videos and Music contained all of my Music tracks around 16,000.
Most likely the Music playlist size is causing the daily library update to send out the delete playlist messages.
I have changed the music library path without success.
Anybody else had this problem caused when Catalina binned iTunes , I still have a sub folder called iTunes under the Music Folder , but playing with the library paths was unsuccessful. I even moved the Movies to a folder outside Music so I suspect the music library update is not completing as the Home Video playlist is always there.
I contacted support without any success and a recommendation to leave it alone as at least Sonos is playing the Music
Best answer by James L.
Duplicate playlists can be caused by having more than one “ITunes Music Library.xml” file in the share path. Have a look through the folder where Sonos is pulling from and check to see if there are more than one copy of this file. If you find more than one, don’t delete any, but move a copy out of the directory and update your music library again in Sonos, then check to see if the duplicates have disappeared. Bear in mind that the duplicate XML may be hidden inside a subfolder and not in the root of the folder path.