[dcol]

I know this is an old thread, but I do encounter kodi not playing some mkv files from the video library. They play just fine in VLC and MX Player. Is there a codec I can install maybe.
Using Kodi 17.6

[Klojum]

It's not a good idea to continue old threads, so I've split off your post. Lots of things can change in the meantime.

Other than that, "not playing" is not very detailed. Please provide a debug log (wiki) file for starters.