You may have ad/mal-ware. Further information can be found in this article; https://support.mozilla.org/en-US/kb/troubleshoot-firefox-issues-caused-malware?cache=no Run most or all of the listed malware scanners. Each works differently. If one program misses something, another may pick it up. ------------- Type '''about:config'''<enter> in the address bar. If a warning screen comes up, press the '''I Accept the Risk''' button. At the top of the screen is a search bar. Type '''browser.startup.homepage''' What is the value? Right-click and select '''Reset''' to restore its default value; '''about:home'''