I have a Macbook Pro (Late 2011) running macOS Sierra that cannot recognize any audio devices. No headphones, no speaker, no microphone. I currently use a USB audio card, which works fine but isn't convenient.
I have tried to fix this by:
I also booted into my Windows partition which did not recognize any audio devices either. So, it sounds like it is hardware related. Any ideas on what can knock out all incoming and outgoing audio at once. I opened it up and didn't notice any disconnected cables or anything of the sort.