Why do I need internet to playback files?

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?

Hello and welcome to the WD Community. 

What firmware are you running on this media player.

I use mine without Internet connection and it plays a lot of different files. 

Have you tried resetting the unit?

this is a very old bug… yes it will sometimes trigger this bug when not connected to the internet…   i thought that was enough connecting the first time