@herman

From our online help http://support.pogoplug.com/entries/472059-i-bought-an-open-box-pogoplug-why-...

'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 your Pogoplug at my.pogoplug.com.'

If you can't reach the original owner, please submit a Support ticket and we'll help you out.
http://support.pogoplug.com/anonymous_requests/new

KR
Christopher