My 12.04 had same problem. I fixed it with part of Pavel Fisher's solution above. Here is what I did:
1) disable autospawn: /etc/pulse/client.conf -> autospawn = no
2) kill pulse: pulseaudio --kill
3) go to Ubuntu Software Centre. Remove pulseaudio then install it.
My 12.04 had same problem. I fixed it with part of Pavel Fisher's solution above. Here is what I did:
1) disable autospawn: /etc/pulse/ client. conf -> autospawn = no
2) kill pulse: pulseaudio --kill
3) go to Ubuntu Software Centre. Remove pulseaudio then install it.