I recently bought a WD TV Live and have always use the older models not connected to any internet connection.
On this new latest device I happened to have it connected to my WiFi network which was online. I was playing back some MKV files without any issue. I then moved house and just ran it unconnected as I have no internet connection there yet. I tried playing back the same files off the same usb drive and it said they were an unsupported format.
I then connecting to WiFi on my iPhone personal hotspot and tried playback of the same "unsupported " files again and then they successfully played.
What the heck is going on?