win10 Logitech 9000 usb webcam in blueiris

[Lepelot]

Go into Camera Properties - then Audio tab - On the top there are 3 radio buttons, select "Other DirectShow device". Select the Microphone for your c920. Click OK.

Alternate option is to just uncheck box "Enable audio channel" at the top of Audio tab)

I just had this same problem and this suggestion worked for me; thank you.