I am pretty sure if I go to Tools -> Options -> File Locations and change the folder MC28 looks in for Series Cover Art</snip>
We cannot specify "the folder MC28 looks in for Series Art"
We can only specify a folder for cover art. With that folder specified, MC will then look for/create subfolders inside there...
- "Albums" is where your album cover art images will go if you have audio mode set to "In a specified folder".
- "Artists" is where you can save artist image files, and, if the folder exists and contains an image file matching an artist in MC, MC will use that image as a thumbnail in artist views instead of fanned cover art.
- "Series" and "Season" folders which, again, MC will scan and use any matching art found.
There are (or can be) more. I'm almost certain you can create a "Composer" folder in there and save, erm, composer images inside it. If it exists, and MC finds matching composer images, it will use them in "Composer" views.
Back in the day, IIRC, all the movie art was saved in a "Video" sub-folder, but conflicts began to happen, so these were moved to "beside the file". I think this folder is only used now for things like blu-ray discs and such.
The point of all the rambling above is to try and demonstrate how much of the thumbnail display in MC is automated. Specify the root "Cover Art" folder in MC settings, and then as long as these sub folders exist and contain matching artwork, MC will just use them.
marko, I'll double check, but I'm pretty sure everything you suggested is true for my "set up".
I cannot see how your shows are tagged, but trust you implicitly
Your "Cover Art" setting definitely needs to be corrected.
Why does MC28 even ask if I want to move my Cover Art? What should my response be if asked?
It's good that it asks. It means everything is moved to the new location and all the thumbs still work. Personally, in this scenario, I would first, make a manual backup of the entire current art work folder. When asked by MC, say "No".
Make certain that MC is able to both read and write to the specified cover art directory. You are using a NAS. I do not have any experience with those, but see a pretty steady stream of people posting about odd issues, and it seems, there's always a NAS involved in there somewhere. I don't know why that is. MC not having the correct access permissions is often a thing, along with "mapped paths" vs "UNC paths"
With the art path correctly set in MC, exit the application. Delete the contents of S:\Cover Art\, and then, from your backup made earlier, move your artwork into the correct subfolders of S:\Cover Art\
Now relaunch MC, and, if all is good, it should "just work". (MC may need to go through the thumbnail creation process again, but it will do that on the fly on demand)
If it doesn't work, I'll be all out of ideas. Good luck