Each Pogoplug device is associated to an individual user account. Since the Pogoplug service is designed to be private and secure, once a Pogoplug is associated to an account, it must be “unregistered” before it can be transferred to another account. 

If you are in contact with the original owner, ask them to sign in to my.pogoplug.com, click Settings, and then click Unregister next to the name of the Pogoplug. Once this is complete you can go through the normal activation process to activate Pogoplug at my.pogoplug.com.  If you are not in touch with the original owner, please submit a support ticket to support@pogoplug.com.