Movies not playing to the end, stops playing and goes back to main screen

SO i have this issue that when i play MKVs th emovie stops like about an hour in to the movie and will not play again, keeps gong back to the main screen, i have to actually skip forward to a couple of minutes to work. Any ideas guys?

Thanks 

That’s a pretty good sign of a corrupted encode.  You might try running the file through MKV merge to see if it can fix the file…