Try resetting your Home Page. See - [[How to set the home page]]

https://mozilla.org/|about:preferences

|about:preferences
|about:preferences#general

|about:preferences
|about:preferences#general

As you have discovered, Firefox allows multiple tabs as your home page, and unfortunately, it's a little too easy to make the Options page one of your home tabs. But you might be the first person to have four copies! I'll just expand on the above reply with a little more "step-by-step" detail. My examples include two pages, and it's the same principle with more: another vertical bar followed by another address. To edit out the unwanted pages, you can use either of these methods: '''''Options page''''' Switch over to the Options page, and select General in the left column. Toward the top of the page, in the Startup section, check the Home Page field: Look for a vertical bar character. As a simple example with short URLs: https://mozilla''.''org/|about:preferences The bar definitely can be hard to spot with long URLs, but when you find it, delete whichever of these you find -- |about:preferences |about:preferences#general -- I suggest deleting the bar last so things don't accidentally get mushed together. Firefox will save the edit when you tab out of or click away from that box. ''Don't click the "Use current pages button" or you'll have to start again.'' '''''about:config Preferences Editor''''' (1) In a new tab, type or paste '''about:config''' in the address bar and press Enter/Return. Click the button promising to be careful. (2) In the search box above the list, type or paste '''home''' and pause while the list is filtered (3) Double-click the '''browser.startup.homepage''' preference and remove whichever of these you see -- |about:preferences |about:preferences#general -- I suggest deleting the bar last so things don't accidentally get mushed together.