I had the same problem for over a year and finally fixed it yesterday. My WD 2T Elements wasn't showing up, on my Mac, and Disk Utility would spin forever without finding it. I fiddled around with Terminal after reading this article http://www.theinstructional.com/guides/disk-management-from-the-command-line-par t-1,
and basically by simply typing: diskutil list , i was able to see it in terminal. Then i tried everything, from erasing the disk although it had valuable albeit unusable data but couldn't unmount. Long story short, while failed, but forgotten plugged in the usb, after 30 minutes or so i 've noticed it on my Desktop. So i have transferred all the valuable files to another drive, and reformatted it as Mac Journalled. The compatibility of eXfat i had previously formatted it seemed to mess things up. Since then i have tested it several times, and have been using it. Hope that helps. If it does, please come back and rate this so others will benefit. Good luck!