If you want, tell me the platform and give an example file symptom (player, behavior) and I’ll give the exact command sequence for that case.

mkvmerge --clusters-in-meta-seek -o web_stream.mkv source.mkv

If you have a file that won't let you skip forward, do not delete it. Use MKVToolNix or FFmpeg to remux the file. This process takes only seconds and generates a fresh index, instantly fixing the playback issues.

When a media player "indexes" an MKV file, it creates a map of where frames are located. Without a proper index, seeking (fast-forwarding/rewinding) can be slow or buggy. The Best Tool