Does it change back pretty much immediately, or when you exit Firefox and start it up again? The home page and search engine settings are separate, but are both changing at the same time? There are a few different ways that your home page could get changed at startup: (1) An add-on changes it (2) An optional settings file named user.js changes it (3) External settings protection software changes it For #1, you can review and disable unrecognized/unwanted extensions on the Add-ons page. Either: * Ctrl+Shift+a * "3-bar" menu button (or Tools menu) > Add-ons In the left column, click Extensions. Then cast a critical eye over the list on the right side. ''None of these come with Firefox, they are all optional.'' For #2, try using the steps in this article: [[How to fix preferences that won't save]]. To see the full names of .js files, you may need to change a Windows setting. This Microsoft support article has the steps: [http://windows.microsoft.com/en-us/windows/show-hide-file-name-extensions]. For #3, some utility programs (like Advanced SystemCare) and some security programs will "roll back" settings changes between Firefox sessions. You may need to turn off the home page/browsing/surfing protection feature of such software until you have everything set just right. Any progress?