I decided to make a new thread, although I know there are already a couple on this topic. Most of my users don't have any such problems, but 3 users have said they sometimes get logged out, and it's not due to inactivity as they have the "stay logged in" option ticked. They use a variety of browsers. (Recent version of Firefox, old version of IE, Opera etc). From Jake's post in the other thread on this topic: Although the server isn't behind a proxy, I've noticed that two of the users who reported the problem are connecting through proxies. The third user has dynamic IP assignment. Could these kinds of connections cause this problem? None of the other possible causes mentioned by Jake in the post above (1, 2, 4) seem to be present in my configuration.