How to attach an Authenticator to your Battle.net account

An authenticator is on the Battle.net account that you did not add.

Information on using the same Battle.net Authenticator on more than one Battle.net account

Information on unlocking the four extra backpack slots in World of Warcraft, and what happens when you remove your authentication features

What to do if the serial number at the back of the physical authenticator is scratched off

What to do if you can't resync your authenticator.

Information about this error message and what it means.

Information about securing an account that is getting verification requests that they did not initiate

How to set up the same Authenticator on more than one device.

What to do when a physical authenticator gets out of sync