Most certainly its due to MM.DB, that's the database that contains all track information among other things. Perhaps the DB became corrupted somehow.

Edit: Oops, accidentally posted twice when I meant to just edit the first post. Didn't notice until it was too late to delete the post.

I was having the same problem. I still don't know exactly what caused it, but the way I got album art working properly again was by uninstalling and reinstalling MediaMonkey. I had everything backed up with trixmoto's [url=http://www.mediamonkey.com/forum/viewtopic.php?t=7746]Backup script[/url], so then I restored my scripts and skins.

The problem might be a setting change or a corrupted library or something; it worked when I uninstalled and reinstalled, stopped working if I did a full restore using the Backup script, worked when I uninstalled and reinstalled again, and kept working when I manually restored just my scripts/extensions and skins, so I figure the problem can't be the scripts I was using or the version of MediaMonkey (since I reinstalled using the same install package as before - it was still in my downloads folder). In fact, the only two files I didn't restore the second time were MediaMonkey.ini and MM.DB, so I think the problem would almost certainly have to be in one of those, though I don't know which and don't want to test them and have to uninstall and reinstall for the third (and possibly fourth) time tonight.

[quote="nohitter151"]Works fine here, are you sure that all tracks are really in the same album (which requires not only the same album name but also the same album artist across tracks?)[/quote]
yeah, don't work! :D

Mizery_Made - appreciate the suggestion. i'll wait for final release - this isn't a big issue, but a bug now and again - pleased if it's fixed...

[quote="fugusushi"]vs. 3.0.7.1191 and 3.0.4.1185 - ''Albumn Art - Apply to all tracks on the album'' does not work! have to do each individ. track. used to work - perhaps it was a previous vs. before 3.0.4. (Vista Home Pre.)[/quote]
Works fine here, are you sure that all tracks are really in the same album (which requires not only the same album name but also the same album artist across tracks?)

I do believe there have been a few bugs fixed in the 3.1 Test Builds involving the "Album Art - Apply to all tracks on the album" options, so it's possible this bug has been fixed. If you are interested in trying the next version out and seeing if this bug has been fixed, you can check the Beta forum. The version is in that latter stages of development and testing, thus it [i]should[/i] be rather stable, though if you do venture into using that build, you should take the advised precautions in the thread containing the Alpha/Beta/RC builds.

vs. 3.0.7.1191 and 3.0.4.1185 - ''Albumn Art - Apply to all tracks on the album'' does not work! have to do each individ. track. used to work - perhaps it was a previous vs. before 3.0.4. (Vista Home Pre.)