You could try this add-on it may possibly fix things. *https://addons.mozilla.org/en-US/firefox/addon/places-maintenance/ If you visit the sites again the icons should be stored again and so reappear. Also especially as there is a possibility you are getting corruption of your Bookmarks database it may be a good idea to ensure you do regular backups of the bookmarks, or better still of the complete file ''places.sqlite'' *[[Restore bookmarks from backup or move them to another computer#w_manual-backup]]'''_manual-backup''' *[[Profiles - Where Firefox stores your bookmarks, passwords and other user data#w_how-do-i-find-my-profile]]'''_how-do-i-find-my-profile''' **http://kb.mozillazine.org/Places.sqlite The ''places'' file is within your ''profile''. The quickest method of finding your profile is to use ''troubleshooting'' as explained in the above article.