Unable to see or delete embedded subtitle

Help
1

When I open the mvk file the embedded subtitle file does not appear I add an srt file and it appears over the original. I am unable to remove original sub.
Can anyone help please?

2

Welcome!

There are several possibilities here:

  1. The subtitles are hardcoded into the video. There’s really nothing you can do about that, neither with MKVToolNix or any other tool.
  2. The type of subtitles isn’t supported by MKVToolNix. You might be able to remove them with other tools, though.
  3. The subtitles in question are actually closed captions & embedded into the video track (interspersed with video frames, not encoded into them), which MKVToolNix doesn’t support. Same as 2., really.
  4. The subtitles aren’t their own track but actually an attachment. Highly unlikely, but possible. In that case you’d find them on the “attachments” tab where you could disable muxing them.