Just did the upgrade and it went smoothly-I THOUGHT. Now strange issue. Some videos, the sound is distorted. Some all is OK. Computer sound card is top of the line. All AVI videos and music files including WAV on my system are fine. It is only when I play SOME videos in a browser ( I use and tried all three-FireFox, Chrome, and Internet Explorer-same issue). It does not matter whether it is at YouTube or any of several news sites I have tried, the issue persists randomly. I have a very high end desktop computer that I built myself, so proprietary software or hardware is very unlikely the issue. This has to be some codec issue with 8.1 and could be a game changer if Microsoft doesn't fix this VERY annoying glitch. Its too bad, because 8.1 is faster and better than 8 on my system. Anyone else experiencing this issue?