I was hangin' round with my computer listening to a radio stream when the sound stopped. Just like that. I'm using Ubuntu 14.04 LTS, and a 4 series KDE desktop.

Symptoms include - from Kmix - concerning playback streams, 'cannot add view, GUI profile is invalid'; and 'nothing is capturing audio'.

I thought to re-install K-mix but Synaptic would not let me do that without doing it to KDE desktop as well, so I thought I'd go the whole hog and install the latest KDE desktop.

I found and used some instructions which looked the part and about seven minutes in I heard a 'pop' from the speakers. I eagerly re-started the machine and was disappointed to find that everything looked the same. But - the sound worked!

Next time I started the thing silence had returned. Can someone suggest a less drastic way of restoring the noise?