I don't know; it doesn't happen to me. This article may help: https://support.mozilla.org/en-US/kb/recover-user-data-missing-after-firefox-update

i was not logged into a profile. i have not logged into one until i read the article. i now have a profile and i an logged into it.

You always have a Firefox profile to store your personal data although you may not have been aware of it. Are there backups available in the Bookmarks Manager (Library)? *https://support.mozilla.org/en-US/kb/recover-lost-or-missing-bookmarks *https://support.mozilla.org/en-US/kb/restore-bookmarks-from-backup-or-move-them ---- You can check if you have an "Old Firefox Data" folder on the desktop in case the Refresh feature in Firefox has been used and a new profile has been created. *https://support.mozilla.org/en-US/kb/reset-firefox-easily-fix-most-problems *https://support.mozilla.org/en-US/kb/recovering-important-data-from-an-old-profile