I had some videos that played without sound and almost deleted them, then decided to see how it ran through my TV and it worked perfectly, (server is synology linux, I’m watching on windows 11) so this is a way to test if your issue is just windows. Also, opening the videos with Windows Media Player gave me a popup about the missing EAC3 audio codec making it very easy to find the issue.
I have the latest software install and a FRESH copy of windows 11, NOT an upgraded copy. If you play Videos with EAC3 audio codecs, you’ll get an error saying you’re missing it. Windows claims they removed it from 11 as so many vendors install it they thought it was unnecessary. If you upgraded from 10 you won’t have this issue.
The SAFEST fix is to install the Dolby Audio system from the windows store (link below). There is a guide out there suggesting you disable windows defender to install a solution it sees as a virus and many report it doesn’t even work, better to avoid I say.
All I found searching was 2-3 year old topics that were locked from replies so decided to make a new one since this issue is renewed with fresh copies of Windows 11