Hi serdhex, Thank you for your question, I understand that you are asking what happened to your email sync account for Firefox Sync. In version 37 old accounts are migrated to the new Firefox Sync that was introduced in Firefox 29. Are you signed up at accounts.firefox.com or account.services.mozilla.org? The later is the older version of Sync: *[[How to update to the new Firefox Sync]] If you were already on the new version of sync, please consider backing up the current profile and changing the email password. If it says the account does not exist, it is easy to sign up for a new one, however the account previous will not be accessible.