Apple TV
I try signing in to my Apple TV to update the YouTube app and there is an unknown email address that shows up that I do not recognize or ever used. I can't seem to get rid of it.
Question marked as
Delete the app, then re-install from the on-device App Store.
Apps stay linked to the account that originally installed that app, for App Store purposes, including app updates. If you use an Apple TV box that has had a previous owner, and that hasn’t been reset for your personal use, then this might happen.