No, that isn't possible. You can add a secondary email account, but this is only possible if you have access to the primary account, so you would have to do this in advance before you lose access to the primary account. *https://support.mozilla.org/en-US/kb/change-primary-email-address-firefox-accounts *https://support.mozilla.org/en-US/kb/forum-response-firefox-sync-verification-email-faq ---- Note that Sync isn't meant to be used as a backup and you should always backup your personal data locally. *https://support.mozilla.org/en-US/kb/back-and-restore-information-firefox-profiles *https://support.mozilla.org/en-US/kb/restore-bookmarks-from-backup-or-move-them