This answer explains how to use the WD Quick Formatter to format a WD external drive in Windows (8, 7, Vista, or XP) and Mac OSX (Leopard, Snow Leopard, Lion, Mt. Lion, or Mavericks).*END Important: • The WD Quick Formatter is ONLY for external drives. Once the WD Quick Formatter is finished reformatting the drive, the drive will only have one partition. This is necessary in order to optimize the performance of the drive. • The WD Quick Formatter is the recommended way to format WD external drives that use Advanced Format Drives (AFDs). • The instructions in the articles below are designed to help users reformat and repartition an external drive. This process is Data Destructive and cannot be undone.