I see... thanks again! Actually I was waiting for a replacement for FavIcon Reloader, but at the moment it does not seem to be possible to port its functionality to the new addon-ecosystem. I think that's why the developer could not update it for newer versions of firefox and it is the reason why I came up with this workaround. With 10.000 bookmarks you could always backup/restore your favicons.sqlite, favicons.sqlite-shm and favicons.sqlite-wal files in your profile folder or let this extension run for two hours and turn of the heating instead ;) Maybe, on the other hand side, you can reduce your number of bookmarks by finding many dead links...