I'm a member of a book club that meets once a month at our local library. Many months, we have at least one remote participant; we use Skype to bring him/them into our discussion. We have a webcam that enables them to see us and an external microphone so that they can hear all of us. We then use an LCD projector to display the Skype video so that everyone in the room can see the remote participants. This has worked relatively well for a few years now.

Yesterday, we had an odd experience with the external microphone. Our remote participant complained that he found us very loud, much louder than normal, even though he had the output from his computer speakers was turned down to 1 (%); he asked if I could turn the volume down at my end. I found the microphone in my Recording Devices and found that the level was 79; I turned it down a lot (to 33 for a start) and he said that was a lot better. Problem solved? Not really. I watched the level on the microphone and found that it started creeping back up quite steadily; in just a few seconds, it was back to where it had been and even higher. I lowered the volume again; it just crept back up. Several more lowerings revealed that the level automatically went right back up, sometimes right to 100, within seconds. I went to the advanced tab and tried unchecking the checkboxes I found there in case one of them caused this behaviour but, even unchecked, there was no change in behaviour: the input volume just went right back up.

Why is this happening and what do I need to do to make the level stay where I put it? (I'm also curious to know why this should suddenly be a problem *now* since it wasn't a problem previously. Did a recent Microsoft update cause this issue?)