When I turned on my iMac (MacOS Sierra) this morning, the video I tried to play did not play any sound. My volume icon is greyed out. I looked at the Outputs from the Sound Preferences. I do not see "Internal Speakers" at all any more.
There is no change when I plug in my headset.
The first sound comes out when the system starts.
I tried to treat lightly touching the toothpick through the headphone output but this did not happen.