I can think of three possibilities for getting multiple tabs at startup: '''(1) Session Restore''' Firefox could be set to restore your previous session (first checkbox on the Settings page) or could believe that it needs to recover from a crash. Are you closing the unwanted tabs before quitting Firefox? To quickly multi-select tabs, you can make the first or last tab active, then shift+click the tab at the other end of the range, then right-click any selected tab and "Close # tabs". Can you tell whether Firefox is shutting down normally? To give it the best chance, use the menu -- * menu button > Exit * (menu bar or Alt+F) File > Exit -- and allow a minute before shutting down the computer. ''If you are getting old tabs and #2 doesn't help, we can move on to cleaning up old files.'' '''(2) Multi-Tab Home Page Setting''' If you get the same tabs in a new window (Ctrl+N), it's most likely a problem with your home page setting. See: [[How to set the home page]]. If a new window is normal, another possible explanation is that the shortcut you use to start Firefox has been modified with a bunch of URLs. But that's a lot of tabs, so this seems less likely. '''(3) Add-on feature''' You can view, disable, and often remove unwanted or unknown extensions on the Add-ons page. Either: * click the Extensions button (puzzle piece) on the toolbar > Manage Extensions * Ctrl+Shift+a (Mac: Command+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. On the right side, find the "Manage Your Extensions" heading. ''If there is at least one extension before the next heading -- "Recommended Extensions" -- please continue:'' Then cast a critical eye over the list below that heading. 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). For your privacy and security, don't let mystery programs linger here. Any improvement? ''Note: Sometimes extensions can frustrate access to this page. In that case, first restart Firefox in its Troubleshot Mode and then try again.'' See: [[Diagnose Firefox issues using Troubleshoot Mode]] -- Open, not Refresh.