Aaaaarrrrrgh, so frustrating!
Its not only the WD TV HD.
I’ve had the same problems with my WD TV LIVE HD.
When viewing a movie (MKV) it either freezes, stops mid way, or the sound is “all of a sudden” out of sync…very frustrating.
It happens 2 out of 3 times.
Sony have a great new Blu Ray Player (SONY BDP-S370).
It supposedly supports MKV files. (And MP3 music!)
My patience is starting to dwindle and the Sony is starting to look very attractive.