What is the URL of that start page? You can delete the formhistory.sqlite file in the Firefox profile folder to remove all stored form data. You can use this button to go to the Firefox profile folder: *Help > Troubleshooting Information > Profile Directory: Show Folder (Linux: Open Directory; Mac: Show in Finder) *http://kb.mozillazine.org/Profile_folder_-_Firefox ---- You can remove all data stored in Firefox from a specific domain via "Forget About This Site" in the right-click context menu of an history entry ("History > Show All History" or "View > Sidebar > History") or via the about:permissions page. Using "Forget About This Site" will remove all data stored in Firefox from that domain like bookmarks, cookies, passwords, cache, history, and exceptions, so be cautious and if you have a password or other data from that domain that you do not want to lose then make a note of those passwords and bookmarks. You can't recover from this 'forget' unless you have a backup of the involved files. It doesn't have any lasting effect, so if you revisit such a 'forgotten' website then data from that website will be saved once again.