Just wanted to give a heads up that an unofficial manual update to Sync 3 version 3.0 has been made available here:
http://www.mustang6g...ead.php?t=90236 (I used the second mirror for the file)
It has been installed on Ford Fusion's, F150's and Mustangs with Sync 3. It is confirmed to fix the album art issue with the media player on USB music.
I think Ford only releases a single file for Navigation equipped vehicles, so in theory it should work for the MKZ.
I may try this later today. I will post my results. If anyone else trys the update, please post your results.