I have a Lenovo X1 Carbon running windows 7. When I plug in headphones the internal speakers do not mute. Also, the mic input seems to come from internal mic, even when a headset is connected.
The headphones DO work, but in parallel to the speakers.
I updated my audio drivers from the Lenovo site running version 126.96.36.19910 from 21/Aug/2012.
This is really annoying. Any suggestions that may solve it?