What theme are you using? [https://support.mozilla.org/en-US/kb/troubleshoot-firefox-issues-using-safe-mode Start Firefox in Safe Mode] {web link} A small dialog should appear. Click '''Start In Safe Mode''' (not Refresh). Is the problem still there?

Sounds like a problem with the favicons. You didn't use this profile with an older Firefox version? Do the favicons reappear when you click a bookmark to open the link in a tab? ---- If you use Sync then best is to disconnect Sync temporarily during troubleshooting. You can check for problems with the <b>places.sqlite</b> and <b>favicons.sqlite</b> files in the Firefox profile folder. *use "Verify Integrity" button on the "Help -> Troubleshooting Information" (about:support) page In case errors are reported with "Verify Integrity" close and restart Firefox and retry. If "Verify Integrity" cannot repair places.sqlite then remove all <b>places.sqlite</b> and <b>favicons.sqlite</b> 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 See also: *https://support.mozilla.org/en-US/kb/Bookmarks+not+saved#w_fix-the-bookmarks-file *https://support.mozilla.org/en-US/kb/fix-bookmarks-and-history-will-not-be-functional 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:preferences</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