I just had the same problem on Ubuntu and find that /etc/shadow was in the root group (bad upgrade?).
Make sure you have the right owner, group and permissions. $ ls -l /etc/shadow -rw-r----- 1 root shadow 3180 May 15 16:56 /etc/shadow This may become a feature request on PAM: on a problem to read /etc/shadow, log an useful message in syslog instead of 'user unkown'. -- To UNSUBSCRIBE, email to debian-bugs-dist-requ...@lists.debian.org with a subject of "unsubscribe". Trouble? Contact listmas...@lists.debian.org
