I am running into some very strange issue with loopback capture 1) Open a loopback capture stream on default audio endpoint (headphones) 2) Play audio using WMP. This audio gets captured in loopback stream 3) Terminate audio playback using ctrl+w shortcut. At this stage, you'll get a buzzing sound from my headphones. This buzzing sound will go away only after I terminate loopback capture. Does anyone have any idea on how loopback capture can affect audio going out on the device? I am using sample code at and modified it to not stop capture when flags are non-zero. http://blogs.msdn.com/b/matthew_van_eerde/archive/2008/12/16/sample-wasapi-loopback-capture-record-what-you-hear.aspx Thanks