I have just updated to 1903, and have lost all sound. I have a Creative Audigy2 ZS Pro, yes, I know it's old, but it was working perfectly on build 1809.
After this 1903 update, no sound, so I went back to 1809, and hey presto, I got my sound back. I then tried the very latest 1903 build, but lost the sound again. Have MS got an answer? I will have to go back to 1809 if I want to hear anything, but can wait a day or so if anyone at MS can give me a solution.