I created a sync account with an incorrect email address that turns out is a valid email address belonging to someone else. In Firefox, the sync account setup process took me through selecting what I'd like to sync and then went to the email verification step. I wondered why I didn't get the verification email, and that's when I got what happened. I disconnected the incorrect sync account from Firefox. I've since made a sync account with the correct email address. The incorrect one is stuck in the state of "A verification link has been sent" on accounts.firefox.com. I thought I'd try to access https://accounts.firefox.com/settings/delete_account directly, but it kicks me back to the notification that "A verification link has been sent." I read through the posts here: https://support.mozilla.org/en-US/questions/1154121 One of the moderators said, "If you can't answer the confirm email and have never used the account then it is very likely that any data has been uploaded to the Sync server." I think they meant "unlikely." I just don't want to assume, nor would I want the owner of the incorrect email to be able to reset the password to the account and access my data. Anyway, thanks ahead of time. It's impressive you're all volunteers!