I have checked their website and other websites, and nobody has this issue with their Honestech HL DVR device. However, if you are on Windows 7 or higher, right click the sound icon on the system tray, then choose one of the available options and go to Communications. It's known that this option mutes the audio, even if there is no communication going on through the available applications. Choose Do Nothing and then restart the DVR application. It should work now.