Shortcut Keys not working for .mkv files in MPC-HC

Hi, The Shortcut keys for Jump Forward(Keyframe) and Jump Backward(Keyframe) are not working for .mkv files but are working fine with .mp4 files.
I also reinstalled my K-Lite Codec Pack

Does it also happen if you disable hardware acceleration in the video decoder?

It should work normally for any video that has a valid keyframe index.

Nothing changed after disabling the Hardware Acceleration

Problem updated: I found out that .mkv files with codec ID V_VP9, format VP9 are having this problem whereas .mkv files of codec ID V_MPEG4, format
AVC aren't having this problem. here is the media info those two files

First file



Second file

That file might not have keyframes. It is probably the fault of Internet Download Manager. I have seen that program make 'bad' file several times before.

I use this plugin for Firefox, and that same YouTube video seeks fine after downloading.
https://addons.mozilla.org/en-US/firefox/addon/youtube-video-and-audio-dow/

You can probably also fix the file by remuxing it with MkvToolNix.

But It was working fine before the system reset(Yes, I did reset the system). does it have something to do with the windows update ?

Thanks for suggesting MkvToolNix. It did the trick. but it is a very frustrating task to first download the video and then making its new copy by remuxing it. I want it back normal

It is the fault of the downloading tool. Perhaps you used a different version of IDM before your reset? I suggest reporting this problem to them, so they can fix their Matroska muxer. Or you could use a different download tool.