try this might it help you
From the navigation, select Access > Users. The Users — Main page is displayed. From the Storage complex list, select a storage complex. The table displays the users that have been assigned to the Basic Authentication policy on the selected storage complex.
Select a user, then select Unlock user from the Action list.
A confirmation message is displayed, click Close.

Back up all personal data, then factory data reset.

Hello My name is Walter, have a Xperia X10, want that they help me to find the way to unblock the account of user for ingresar and change my password since my son change the password by error and forget him .