[nc8000]

I have started using my iBasso D1 via usb with my pc in my home office and have come across a thing that I don't understand. The Vista volume control does not seem to work when sound is send through the D1 neither does the mute operation. I can adjust the volume in the variuos applications like media player, iTunes etc but the master volume/mute does not work. It works when sound is piped through the standard line-out/headphone out of the pc and it worked with the D1 when I first hooked it up but after a reboot of the pc it has not worked since. I'm stumped.