I have been having this problem ever since I upgraded from Firefox 3 to Firefox 4. Every now and then my e-mail and website logins, Google search settings, etc. get reset - I assume because Firefox either deletes the cookies or stops using them for some reason. Firefox is set to "Remember history". I'm not using any sort of antivirus or other software which would periodically clear my cookies. Most cookies are set to expire in 2012 so it's not like they are expiring a few days later. And it happens for '''all''' my logins and settings at the same time, anyway. This never happened in Firefox 3 - I could stay logged in my favorite forums and e-mails pretty much forever. Furthermore, I can't see any pattern in it. It seems like it's pretty much random. Although there's usually a few days in between it happening.