The change should remain until you change it again. And the change should affect all the standard searches so it should be the same search engine in the addressbar or if you highlight and right click text within a web page. Is Firefox saving other changes ok ? For instance you can save a bookmark and see the new bookmark still after you restart Firefox. Check to see if you have any toolbars installed that will cause this. Check your Firefox addons, and any programs installed on Windows. Otherwise it is likely to be adware / malware on your computer. See * [[Remove a toolbar that has taken over your Firefox search or home page]] * [[Troubleshoot Firefox issues caused by malware]] Scan with all the tools mentioned as no tool detects everything, and once malware has a toehold you may have multiple issues.