Hi, that does happen sometimes, please try : *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 *https://support.mozilla.org/en-US/kb/recovering-important-data-from-an-old-profile * '''''What's What in the Profile ''''' *bookmarks and history: places.sqlite *bookmark backups: compressed .jsonlz4 JSON backups in the bookmarkbackups folder *cookies.sqlite for the Cookies *formhistory.sqlite for saved autocomplete Form Data *logins.json (passwords) and key4.db (58+) or key3.db (57 and older) (decryption key) for Passwords saved in the Password Manager *if you only have key3.db then make sure to remove an existing key4.db *cert9.db (58+) or cert8.db (57 and older) for (intermediate) certificates stored in the Certificate Manager *if you only have cert8.db then make sure to remove an existing cert9.db *persdict.dat for words you added to the spelling checker dictionary *permissions.sqlite for Permissions and possibly content-prefs.sqlite for other website specific data (Site Preferences) *sessionstore.jsonlz4 for open tabs and pinned tabs (see also the sessionstore-backups folder) fyi for the future : *https://support.mozilla.org/en-US/kb/export-firefox-bookmarks-to-backup-or-transfer *https://support.mozilla.org/en-US/kb/import-bookmarks-html-file *https://support.mozilla.org/en-US/kb/back-and-restore-information-firefox-profiles Please let us know if this solved your issue or if need further assistance.