Exactly.
The cover will be displayed for the Windows File Explorer views also reacheable from
CTRL + SHIFT + 1 to CTRL + SHIFT + 3
and from
CTRL + SHIFT + 7 to CTRL + SHIFT + 8
But not for
CTRL + SHIFT + 4 to CTRL + SHIFT + 6
If you see the cover embedded in Mp3tag (lower left part), the reason is highly unlikely in the mp3 file itself.
It could be some issue with your Window File Explorer thumbnail cache.
Have you tried to copy the file to another folder or rename it with another (short test) filename?
I agree, I don't think Mp3Tag is the issue. I will continue to troubleshoot the issue. Renaming the file and transferring to another folder does not work. I will check for system updates, empty my thumbnail cache and reset my computer.
Just to be sure:
From a Microsoft forum answer:
Open the File Explorer > View tab > Options. Once Folder Options is open, click the View tab and make sure you uncheck the "Always show icons, never thumbnails". Just hit Apply and OK to finish.
In my German File Explorer the option is called:
Immer Symbole statt Miniaturansichten anzeigen
It has to be disabled to show thumbnail pictures.
AFAIK this setting has to be set per folder or must be applied for all folders from the same type.
Yep. already unchecked.