Yet another one of those write this down Jan, it will come up again posts. There’s almost certainly a better way to force log out absent users on a Mac but heck, this works for me.

To kill off all the processes of a user named joe who’s left logged in but used the user switcher, open up the Terminal app and run these commands.

sudo su -
ps aux | grep ^joe | awk '{ print $2; }' | xargs -I{} kill -9 {}

In my kitchen is the community iMac and I have set up accounts for my whole family. Sometimes people come over and forget to log out but used fast user switching to go to the login screen or a different user.

That’s not too bad, but some software combinations I’m running often take up lots of CPU needlessly. Yes, Firefox and Adobe Flash I mean you. The whole iMac becomes slow and unresponsive.

That makes for a sad Mac. More importantly at 5:30 AM it makes for a sad me. As long as you know Joe’s user id then this will zap all of his processes and log him out as a result.

If some of those processes are stubbornly cling to life then rinse and repeat.