What's going on?... the DVD player only plays new motion picture DVDs not previously used, yet plays all, even used CDs on a 27 inch desktop iMac Apple Computer Mid 2010 OS X El Capitan Version 10.11.3, Processor 3.2 GHz Intel Core i3, Memory 8GB 1333 MHz DDR3, Graphics ATI Radeon HD 5670 512 MB