I fixed it. The problem was that the ~/.asoundrc.asoundconf entry for the "default" soundcard was broken:
#------------ BROKEN ---------------- !defaults.pcm.card default defaults.ctl.card default defaults.pcm.device 0 defaults.pcm.subdevice -1 #------------ WORKING -------------- !defaults.pcm.card I82801CAICH3 defaults.ctl.card I82801CAICH3 defaults.pcm.device 0 defaults.pcm.subdevice -1 Here's how I fixed it: (lines starting with $ are shell commands) =================== $ asoundconf list Names of available sound cards: I82801CAICH3 $ asoundconf set-default-card I82801CAICH3 =================== -- "Your audio capture settings are invalid. Please correct them in the Multimedia settings." is a really unhelpful error message https://launchpad.net/bugs/61211 -- ubuntu-bugs mailing list ubuntu-bugs@lists.ubuntu.com https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs