Some ad-ware programs can change your settings without you knowing. You may have ad / mal-ware. Further information can be found in the [[Troubleshoot Firefox issues caused by malware]] article. Run most or all of the listed malware scanners. Each works differently. If one program misses something, another may pick it up. ----------------- '''https://support.mozilla.org/en-US/kb/how-to-fix-preferences-wont-save''' Note: Some software, like Advanced SystemCare with Surfing Protection, can protect files in the Firefox profile folder against changes. If you have such software then check the settings or uninstall this software. --------------------- Type '''about:config'''<enter> in the address bar. If a warning screen comes up, press the '''Be Careful''' button. At the top of the screen is a search bar. Type '''browser.newtab.url''' This tells Firefox what to show when a new tab is opened. If you want, right click and select '''Modify'''. You can change the setting to; '''about:home''' (Firefox default home page), '''about:newtab''' (shows the sites most visited), '''about:blank''' (a blank page), or you can enter any '''web page''' or '''about: page''' you want. The same instructions are used for the new window setting, listed as '''browser.startup.homepage'''.