Hi, check your desktop for a folder called OldFirefoxProfile it may be possible to rescue data out of it. Look for your profile here and rescue it and look for a new profile that has been made : *https://support.mozilla.org/en-US/kb/profiles-where-firefox-stores-user-data *https://support.mozilla.org/en-US/kb/recover-lost-or-missing-bookmarks *http://kb.mozillazine.org/Transferring_data_to_a_new_profile_-_Firefox *https://support.mozilla.org/en-US/kb/profile-manager-create-and-remove-firefox-profiles For removal of Firefox uninstall Firefox. Then Delete the Mozilla Firefox Folders in C:\Program Files , C:\Program Files(x86) & C:\ProgramData Delete the profile Folder as per location top URL or Create a New Profile. If these fail use : https://www.revouninstaller.com/revo_uninstaller_free_download.html Reinstall with Current Release Firefox 59.0.1 with a Full Version Installer *https://www.mozilla.org/firefox/all/ fyi for future : *https://support.mozilla.org/en-US/kb/back-and-restore-information-firefox-profiles *https://support.mozilla.org/en-US/kb/export-firefox-bookmarks-to-backup-or-transfer Please let us know if this solved your issue or if need further assistance.