You can clear all the bookmarks in the three root folders (Bookmarks Toolbar, Bookmarks Menu, Other Bookmarks) in the Library under "All Bookmarks". *https://support.mozilla.org/en-US/kb/how-do-i-delete-bookmark Alternately, you can remove places.sqlite (bookmarks and history) in the Firefox profile folder and remove the backups in the bookmarkbackups folder. Note: you lose the history if you remove places.sqlite. *https://support.mozilla.org/en-US/kb/profiles-where-firefox-stores-user-data