Did you switch to another version like Flatpak or Snap and not Firefox from the Mozilla server as each may use a different location for the profile folder ? *https://support.mozilla.org/en-US/kb/recovering-important-data-from-an-old-profile *https://support.mozilla.org/en-US/kb/recover-user-data-missing-after-firefox-update You can try Firefox from the official Mozilla server if you currently use a version from the repositories of your Linux distribution to see if it behaves differently. *https://www.mozilla.org/en-US/firefox/all/#product-desktop-release