Howto logout a user on "beachballing" Mac OSX Leopard without rebooting machine

If you have often faced applications while running Mac OSX Leopard with X11 that crash and send the system into a Beachball mode that you cannot get back out of using the mouse or keyboard.

There is a way out to "logout" the user without rebooting the machine to regain control

Issue the command

 ps auxwww|grep loginwindow 

Then you will get a list of jobs including the login session

somwhere:~ hari$ ps auxwww|grep loginwindow
jack     91187   0.0  0.1   380400   5756   ??  Ss    9:59AM   0:00.32 /System/Library/CoreServices/loginwindow.app/Contents/MacOS/loginwindow console
jill 56158   0.0  0.1   133488   5168   ??  Ss   Mon10AM   0:06.14 /System/Library/CoreServices/loginwindow.app/Contents/MacOS/loginwindow
robert 12747   0.0  0.1   133232   5160   ??  Ss   Fri05PM   0:04.62 /System/Library/CoreServices/loginwindow.app/Contents/MacOS/loginwindow
jack     92544   0.0  0.0    75412    372 s001  R+   12:27PM   0:00.00 grep loginwindow

 Then you have to kill the pid which corresponds to the "loginwindow console" for the user whose session has beachballed . The machine returns to the Login window without killing other users jobs and allowing any user to log back in

i.e

kill 91187

Then you have control of your machine again. Of course user jack will lose any unsaved changes because of the forced logout  , but at least other users are still logged in.