High Definition Audio Controler doesn't work

[ScottyS]

I hope someone can help me. I stopped getting audio output through the mDP cable (to my monitor's speakers) several months ago. I thought it could be the cable. But I have the yellow triangle with ! over the HD audio controller in Device manager. I've disabled it and I've uninstalled it and tried to update driver (Windows says I have the best driver installed) and Roll Back Driver is greyed out.
Audio output through mDP-to-HDMI adapter doesn't work as well and changing mDP cable doesn't help either.
This started in Win8 before Win10TP came out. I installed Win10TP on a clean partition, and I have the same problem there.

 

[olimjj]

Perhaps reverting back to a restore point, when this was not a problem, might provide a clue as to what "broke" it.

 

[Gavin Lewarne]

it is a problem with the January firmware. it does it on mine and also my colleagues. both of ours are new devices and went from the factory firmware straight to the January one via windows update. strangely, another colleagues that is older and has had updates cumulatively from last July does not exhibit this. so far I haven't found any issues with the particular error. I think its related to the sound drivers for the dock now only activating with sp3 in the dock with the latest firmware.

 

[ScottyS]

It happened many months ago, but if it's a firmware update reverting back to a restore point or doing a refresh or restore wouldn't fix it. Firmware explains why after it was present in Win8 it also exists in Win10 which was installed on a clean partition.

I guess the way to test this is to connect it to a MS dock. Maybe I could bring it to a MS store (but I doubt they have an audio setup to a dock to test).