Since we have figured out the reasons for the MKV file no sound, it becomes much easier to resolve this problem.
Typically, the incompatible audio codec is the main culprit of most Windows MKV no sound issues. You can convert MKV to MP4 with a supported audio codec to settle such errors and play the video on your devices and programs. WonderFox HD Video Converter Factory Pro is a great toolkit to help you change MKV audio or video format to your device-compatible format while keeping the video stream intact.
Now, install the software and see how to fix MKV audio not playing below.