What's your computer system and Firefox version? Do these links help? http://kb.mozillazine.org/Profile_folder_-_Firefox#Navigating_to_the_profile_folder https://support.mozilla.org/en-US/kb/profile-manager-create-and-remove-firefox-profiles https://support.mozilla.org/en-US/kb/how-run-firefox-when-profile-missing-inaccessible https://support.mozilla.org/en-US/kb/back-and-restore-information-firefox-profiles