Do you still have the Firefox profile folder or possibly a "C:\Windows.old" folder ? Location used for the main profile that keeps your personal data (Root Directory on about:profiles). *C:\Users\&lt;user&gt;\AppData\Roaming\Mozilla\Firefox\Profiles\&lt;profile&gt;\ *https://support.mozilla.org/en-US/kb/profiles-where-firefox-stores-user-data You can copy files like these with Firefox closed to the current profile folder to recover specific data. *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<br>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<br>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) See also: *https://support.mozilla.org/en-US/kb/recovering-important-data-from-an-old-profile