I'm also having a problem since running Windows updates on my laptop. I've been running 1Password on my Mac since 2007 with no problems. I'm using Dropbox to keep 1Password synced between the two machines and all was well until I updated Windows. Before the updates I was running IE8 but the updates installed IE9 version 9.0.8112.1624 After the IE9 update, 1Password stopped working with IE9 but Firefox appeared to work. 22 Windows updates were still recommended so I updated all. Now Firefox doesn't work other than very rarely. My problem appears to be a little different than the problem others are having. I unlock 1Password, open the browser, click the 1Password icon, unlock 1Password again as required, click the log-in button in the pop-up window. 1Password fills in the username and password but then it instantly disappears and the page reloads telling me - incorrect username and password. As far as I can tell I'm running the 32 bit version of IE9.