You're most welcome! I am not quite sure what could be the problem really, but since the MKV format is a free format (non-commercial), there could always be some issues taking place. However, as long as I can remember using MKV files and adding there covers - the most of the information and the cover art is being displayed correctly, even without any additional software. My OS is Windows 10 Pro (Ver. 20H2), but even on all the older versions of Windows 10 the MKV covers have still been visible well and I am not sure, if the side Software, such as the "Icaros" by Xanashi really makes a big difference. Sometimes all what it takes - is just to refresh the folder, using 'F5' or possibly installing some other side Software, that deals with the MKV files processing, such as the "MKVToolNix GUI" by Moritz Bunkus. In any case, if the Cover is named as "Cover.jpg" - it can be displayed well and the issue most likely should be resolved, while having specifically that name of the cover attachment, because it's the most standard name used by the MKV files developers. I could be wrong here, but this is how I look at it.