Hello, Some articles maybe help you: *[https://support.mozilla.org/en-US/kb/recover-lost-or-missing-bookmarks?esab=a&s=bookmark&r=7&as=s Recover lost or missing Bookmarks] *[https://support.mozilla.org/en-US/kb/customize-firefox-controls-buttons-and-toolbars?esab=a&s=bookmark&r=4&as=s#w_how-do-i-customize-or-rearrange-toolbar-items Customize Firefox controls, buttons and toolbars] Sometimes if you only restart firefox the icon come back!

Do you have a bookmarkbackups folder with JSON backups? 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) You can check for problems with the places.sqlite database file in the Firefox profile folder. *http://kb.mozillazine.org/Bookmarks_history_and_toolbar_buttons_not_working_-_Firefox *https://support.mozilla.org/kb/Bookmarks+not+saved#w_fix-the-bookmarks-file Are you still using your default profile? *http://kb.mozillazine.org/Recovering_a_missing_profile *http://kb.mozillazine.org/Transferring_data_to_a_new_profile_-_Firefox