WMP rating tag and "unrated"

Using Mp3tag to write any WMP rating tag of 1-5 immediately shows in WMP 12.
But if I write either "blank" or "0", WMP continues to show the last remembered rating, even after restarting, though Windows Properties is correctly showing 0 stars.
WMP is obviously holding on to a rating in its database.
The only way to get a 0 rating showing again in WMP seems to be to do it in WMP.
Is this a WMP bug?

ALSO, when you rate in WMP, you lose some of the extended tag values - I was keeping an eye on the DISCOGS_RELEASE_ID, but it reverts to "ISCOGS_" after using WMP to rate.
I have WMP set to "Maintain star ratings in files" and "Write media info changes to files".

Yes, this is known (?) behaviour of WMP: it deletes user-defined tag fields. So I would never use WMP for tagging.

The update problem: have you tried the following:
Delete the unwilling files from WMP.
Then use Extras>Options>Restore deleted items
This should re-read the tag data and the just deleted files will reappear. I don't know, though, if this also updates the rating.

That works!

It's odd, because WMP reads new ratings tags of 1-5 immediately, but not new ratings of 0 or a blank tag.

But then I have been discovering that an app like WMP after so many versions probably has lots of weirdness deep in its software. I know people hate it, but I still think the way you can display, sort and search your library beats flashier looking players I've seen.

Here's another one:
I have an album that's displaying an old bit of cover art in the library, even though I've updated all individual mp3 cover tags and the system jpgs in the folder and deleted the old Thumbs.db file. . I have no idea where it's getting the image from - could it keep it in the WMP database somehow?

See if there are any files in
%localappdata%\Microsoft\Media Player\Grafikcache\LocalMLS
If so: delete them. The contents of that folder is not relevant for playing and probably rebuilds itself after some time (and is a good target to clean up the system once in a while by deleting it).

Actually, I found them in C:\Users\Me\AppData\Local\Microsoft\Media Player\Art Cache\LocalMLS

800 of them! And that got my folder.jpg showing in the Library again. Thanks!

I have finally found a method of showing the tag art for individual tracks in WMP's Now Playing pane at original size! So with the right size jpgs you can fill the pane instead of being stuck with 200x200 images.I have some albums showing front and back covers side by side. I've boiled it down to e registry edit file if anyone is interested?