My two cents in case it helps I have this problem too ... and I have yet to determine the cause ... I usually find out when I try to play sound or flash with VLC ... so I know it is not caused by another application all of the time.
My solution ... which actually kills firefox is to run ... lsof | grep pcm and then kill the process with snd in it such as firefox 6035 usernamehere mem CHR 116,16 11989 /dev/snd/pcmC0D0p firefox 6035 usernamehere 56u CHR 116,16 11989 /dev/snd/pcmC0D0p Hope that helps I am running Ubuntu 8.04 and Firefox 3 with Shockwave flash 9.0 r124 Add-On -- Sound stops working in Firefox once other applications (Pidgin, Rhythmbox) have played sound https://bugs.launchpad.net/bugs/183917 You received this bug notification because you are a member of Ubuntu Bugs, which is subscribed to Ubuntu. -- ubuntu-bugs mailing list ubuntu-bugs@lists.ubuntu.com https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs
