My in-built mic in my TOSHIBA Satellite P50 worked perfectly until it suddenly stopped working. I’m running Win10 on a 64-bit system. All settings seemed to fit perfectly and Conexant SmartAudio HD device was enabled and selected as default device with correct levels (Microphone Array and Boost) and was not muted and green highlighted. What finally helped was a different sample rate setting! I changed under
Windows -> [Settings] -> [System] -> [Sound] -> under "Input" [Device properties] -> under "Related Settings" [Additional device properties] -> folder [Advanced]
the sample rate under "Default Format” to [2 channel, 16 bit, 96000 Hz (Studio Quality)]
and boom, it worked!
Funnily the default value that is selected with [Restore Defaults] to [2 channel, 24 bit, 48000 Hz (Studio Quality)]
does NOT work! It took me hours to find this out - and I guess it might have changed while working with Audacity.