It shouldn't be a problem to remove this bookmark. If your mouse has at least two buttons then you probably should be able to do this directly on the Bookmarks Toolbar via the right-click context menu. Did you try to open the Bookmarks Toolbar folder in the left panel in the Bookmarks Manager (Library) and select this bookmark? Either the right-click context menu or Delete in the Organize menu (first button on the toolbar in the Library) should allow to remove this bookmark. *https://support.mozilla.org/en-US/kb/how-do-i-delete-bookmark If this doesn't work then there might be a problem with the places.sqlite database. You can check for problems with the <b>places.sqlite</b> database (bookmarks and history) in the Firefox profile folder. *use "Verify Integrity" button on the "Help -> Troubleshooting Information" (about:support) page<br>in case errors are reported close and restart Firefox and retry If "Verify Integrity" button on the "Help -> Troubleshooting Information" (about:support) page cannot repair places.sqlite then remove all places.sqlite files in the Firefox profile folder. Firefox will rebuild places.sqlite and restore the bookmarks from a recent JSON backup in the bookmarkbackups folder. *keep a backup copy of places.sqlite in case a new places.sqlite database has to be created *http://kb.mozillazine.org/Unable_to_process_the_backup_file_-_Firefox See also: *http://kb.mozillazine.org/Locked_or_damaged_places.sqlite *https://support.mozilla.org/en-US/kb/Bookmarks+not+saved#w_fix-the-bookmarks-file You can use the button on the "Help -> Troubleshooting Information" (about:support) page to go to the current Firefox profile folder or use the <b>about:profiles</b> page. *Help -> Troubleshooting Information -> Profile Directory:<br>Windows: Show Folder; Linux: Open Directory; Mac: Show in Finder *http://kb.mozillazine.org/Profile_folder_-_Firefox