Missing Album Artwork after Migrating iTunes to Music

Eventually most of my album artwork loaded, but it's very slow. I left Music open for hours while doing other tasks. Not sure if it downloaded from a database, or if it retrieved the artwork from the files themselves. In some cases I had to find and paste the missing art (or album art I preferred over what Music gave me).

I have 1818 albums, many with custom art covers. These seem more or less to have survived. Lost 98 covers in all - about 5% or so. "Get Album Artwork" recovered 33 of them, leaving me a search and enhance, then add album artwork for 65 albums. Will take hours. Also, when re-adding album covers, be sure artwork is transferring to each track. Haven't quite figured out why/how it refreshes some tracks but not others.

You’re not alone, I now have lots of missing artwork that I had added myself. Unfortunately I don’t know of a solution. I have offloaded my music to a nas for feeding a music streamer and these are copies of the files in the iTunes library and I wonder if I import them if the artwork will come with them because they were embedded in the files.

Re-importing did restore artwork for some albums, but I was still left with many artless albums and I had to do the same as Yellow Delicious and paste art from well known sites. It's a real shame the splitting of iTunes forced this problem on us.

My album artwork did load after a period of time, following upgrading to Catalina and using Music for the first time.

I also noticed that after shutting down my computer overnight, and then restarting the next day, when I opened Music again it did not immediately display all of my album artwork. It took some time for all albums to display.

My library is predominately my own CDs imported into iTunes (previously), with the artwork for albums not automatically downloaded by iTunes but manually loaded. I do this because most of my library is classical music and the artwork that is selected automatically is frequently not the same as what my own CD has.