According to TechJapan, Sony has confirmed that the controller buttons on some PSP units may become stuck and not return to their default position. The defect occurs in part of the initial shipment of PSP units and is caused by excess plastic not being completely removed during the molding and manufacturing process of the outer cabinet. As a result, when a button is pressed, it can become caught on the excess plastic and not return fully to its default position. Sony is conducting a free repair program for users who have PSP units affected by this problem. The defect is not present in PSP units fabricated in 2005 and currently being sold.