Until yesterday, Media Player Classic was working perfectly. Now there is no sound, and I can see that there is a small cross (x) next to the speaker icon in the bottom right hand corner. I've tried everything, but can't get the sound back. I have no sound issues with other programs or with YouTube etc.
Don't know what I've done, but hope that someone can offer a solution.

Windows 10 x64 version 1909
Media Player Classic version (943e342dd)

- - - Updated - - -

Turns out it was the video file, which for some reason had no audio when recorded. Problem solved.