2TB hit a limit on older disk controllers and operating systems, for drives >2GB they need a different partition format and possibly a newer filesystem..
If you cannot return the disk or the cost between 2TB is negligible then you could try putting it into a PC and creating a 2TB partition (non-GPT format), leaving 1TB unpartitioned and see if your system recognizes it then... it might not work though as the drive controller might not be capable of recognizing it.
Anyone putting a disk larger than 2TB into an older system needs to check compatibility first, this is a common issue.. it sucks but stuff like WindowsXP and earlier cannot handle drives that large.