Just to clarify: only the default search engine changes, the home page doesn't change? Usually when you launch a new window, Firefox displays your home page. Did your regular home page get replaced with a Yahoo page? You can check the setting on the Options page: [[Startup, home page, tabs, and download settings]]. Meanwhile, this might be a feature of your McAfee WebAdvisor add-on. It has a secure search feature that according to old forum posts is locked to Yahoo. Can you find a way to turn off that feature? You often can manage extension settings on the Add-ons page. Either: * Ctrl+Shift+a (Mac: Command+Shift+a) * "3-bar" menu button (or Tools menu) > Add-ons In the left column, click Extensions. Then find WebAdvisor on the right eye and check for an Options button. Any luck?