[Bladerunner1962]

Realtek ALC drivers are for analogue and digital SPDIF audio output they are NOT connected with HDMI audio output.

The confusion stems from Intel calling high quality analogue output 'HD'...

If your HDMI audio output has disappeared then it is your Intel HDMI Audio drivers that are possibly an issue (it could be that Windows update has updated them in the background?) Or are you using analogue/Toslink/coax output?

Usually reinstalling the video drivers also reinstalls the HDMI Audio drivers too (but I think there may be a way of just updating the Audio element only?)

If you lost HDMI audio, then reinstalling Realtek audio drivers will have been doing nothing to your HDMI audio situation.

I only use HDMI for Audio/HD Audio.

Yes, I assume, that Windows updated the audio drivers in the background, cause, for arround 30 minutes after Windows 10 installation, the sound was gone.

If I reinstall, the device manger in Windows 10 shows in first step, that it works. But, if you look deeper in the device mgt. there is a remark, that the
device needs more installation. I tried that at least 3 teams, but with same result.
I guess, that Realtek has a driver conflict with Windows 10.

So midwhile I rolled back to Windows 7.
But, I will try that again in some days with Windows 10.

Then I will have again also the issue, with not working 3D output (as descripted before).