Hi,I had a very similar problem with my 93. I had transfer the MKV's from my Mac over my wired network to my iOmega nas and the same thing happened. I thought it was the nas but my Pioneer LX55 played the files fine. So I looked at what else it could be. Next I transferred the file to my pc (also on the same network) and then to the nas. It worked and now the files play fine. So I think it's something to do with FTTP or meta data. As long as I follow this routine the MKV's play fine. I check the files by pressing GOTO and if the player is reading it correctly, it allows you to jump to anywhere in the films timeline. If not, you can't even select the option to navigate into the timeline. Hope this helps. P.S. I also contacted Oppo support but didn't get anywhere and stumbled across this work around through trial and error.