Cover Art on iCloud Missing in Finder

[ohrenkino]

@Craig

I added ALBUMARTIST tag but could not see the field in Finder (File info?) and was unsuccessful removing IDv1 tags. I deleted the .DS_Store from iCloud/Downloads folder but no effect when copy/move a new file there.

What did you try to remove ID3v1 tags and which tag version do you write to the files at all?

See the documentation on tag types:

Preferences and Configuration

You can configure many areas of Mp3tag via the preferences window at Mp3tag → Preferences… or ⌘ , General [Preferences → General] Startup Folder Here you can specify the startup behavior of Mp3tag. None starts with an empty File List. Previous starts with the folder which was loaded the last time you’ve used Mp3tag. Other… lets you choose a explicit folder that is loaded on startup. Genres Use standard genres If enabled, Mp3tag lists the standard genres in the genre field on the Tag Pane…

To remove all tag type that are not ID3V2: tick remove for all except ID3V2.
Then select the files and apply "Cut tag".
To save only ID3V2: set write only for ID3V2.

How did you try to save ALBUMARTIST? if you do not have the field in the tag panel and/or the file list, then you can at least add data for it via the extended tags dialogue.