i had this problem with internet explorer - this was the issue, i was having people log in using https:// and then when they tried to log out via regular http:// it wouldn't log them out correctly - all i needed to do to fix it was to change the logout button to go though https://myserver.com/register/logout and it worked fine... i don't knowt if you have https... but if you do that might be it. BTW, mozilla (which i normally use) logged out just fine. I hate that all the web browsers behave differently it makes testing so much more tedious.