> Just calling 'who' does not display > anything at all. Your file /var/run/utmp may be locked. Try this : ps -f -p `fuser /var/run/utmp` It will show all the processes currently using the utmp file.
A few days ago, I had the same problem. The command above showed me a lot of old and frozen gnome-pty-helper. I killed all of those processes whose PPID was 1, and the who command worked again (with bad data, because the file /var/run/utmp was not up to date). It worked for me... until next occurence of the problem. Good luck. Vincent.