Hi GMadrid, you may want to start with a malware sweep using a reputable tool: https://www.malwarebytes.com/mac/ There are a few different possible explanations for an unwanted sites loading, including: * bad add-on * bad home page setting * crash recovery (if you force quit Firefox, it will try to redisplay the tabs from your last session) -- not addressed in this post (1) I suggest you start up in '''Firefox's Safe Mode'''. In its Safe Mode, Firefox temporarily deactivates extensions, hardware acceleration, and some other advanced features to help you assess whether these are causing the problem. ''If Firefox is not running:'' Hold down the option/alt key when starting Firefox. (On Windows, hold down the Shift key instead of the option/alt key.) ''If Firefox is running:'' You can restart Firefox in Safe Mode using either: * "3-bar" menu button > "?" Help button > Restart with Add-ons Disabled * (menu bar) Help menu > Restart with Add-ons Disabled and OK the restart. ''Both scenarios:'' A small dialog should appear. Click "Start in Safe Mode" (''not'' Refresh). ''Any difference at startup?'' (2) You can view, disable, and often remove unwanted or unknown '''extensions''' on the Add-ons page. Either: * Command+Shift+a (Windows: Ctrl+Shift+a) * "3-bar" menu button (or Tools menu) > Add-ons * type or paste '''about:addons''' in the address bar and press Enter/Return In the left column of the Add-ons page, click Extensions. Then cast a critical eye over the list on the right side. Any extensions Firefox installs for built-in features are hidden from this page, so everything listed here is your choice (and your responsibility) to manage. Anything suspicious or that you just do not remember installing or why? If in doubt, disable (or remove if possible). (3) To update your '''home page''' setting on the Preferences page: * Mac: "3-bar" menu button (or Firefox menu) > Preferences * Windows: "3-bar" menu button (or Tools menu) > Options * Linux: "3-bar" menu button (or Edit menu) > Preferences * Any system: type or paste '''about:preferences''' into the address bar and press Enter/Return to load it In the left column, click '''Home''' Then on the right side, you can switch among the built-in home page and a custom set of home tabs. Can you regain control?