I know many people say MKV's don't work on this but there are reports that they do. I've had no luck.
Some open and just display a black screen and no audio, while others return an "Unsupported Resolution" error. I can understand that resolution problem, but I don't get why some MKV's don't throw an error at all? ... either way I'm converting the MKV's to AVI's to get around the problem.