Do you hit the stop or pause button? When hitting stop it *should* work fine, but if you hit pause, that's likely why it happens. Reason being if you're using WASAPI you're probably using exclusive mode. You'd have to disable exclusive mode for WASAPI (aka use WASAPI shared) or use DirectSound instead. When using either WASAPI shared or DirectSound you're going through the Windows mixer and you'll lose bit-perfect audio output in MC.