Why do some MKV files not play?

Related questions

1. Which has better quality mp4 or MKV?
2. Does VLC play MKV?
3. Can MKV play on TV?
4. Which media player can play MKV files?
5. Does LG TV support MKV?
6. What MKV means?
7. Can I change MKV to mp4?
8. Is MKV better than AVI?
9. Can we convert MKV to mp4?
10. Will MKV play on Hisense TV?

Tags

1. #subtitle
2. #downloading
3. #codecs
4. #supported
5. #players
6. #arises
7. #problem
8. #played
9. #audio
10. #contains
11. #either
12. #cannot
13. #media
14. #files
15. #comes
16. #image
17. #codec
18. #compatible
19. #playing
20. #samsung