I'm not sure how you ended up without an avahi group but it definitely creates one on install (confirmed in practice) and from the postinst script:
if ! getent passwd avahi >/dev/null; then adduser --disabled-password --quiet --system \ --home /var/run/avahi-daemon \ --gecos "Avahi mDNS daemon" --group avahi fi The only thing I can figure is that you created an avahi user manually, e.g. to compile from source or some such which prevented this from running and not creating a group. -- Missing group 'avahi' makes avahi-daemon fail to start https://launchpad.net/bugs/54984 -- ubuntu-bugs mailing list ubuntu-bugs@lists.ubuntu.com https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs