My Passport will not backup (MAC)! Appears on screen, ok in Disk Utility

Hello! I have seen this topic many times but now I am having an issue. I am using a MacBook, I have had this external WD My Passport Studio for 3.5 years. I have used it only a handful of times, the last time September 2015. All worked fine then. Since, I have updated to Yosemite on my MacBook and perhaps this is an issue?

  • When I plug in the hard drive, it appears on my screen, I can open it and everything but when I hit BACKUP NOW it just sits for hours and says “preparing backup” (or something of the sort, I can’t remember exactly).
  • I checked it in DISK UTILITY - verified everything and it said it is fine and ready to use.
  • I updated the software - now using 1.3.7
  • The SmartWare screen opens and only loads the internal hard drive, it doesn’t find the external hard drive.

Have I missed something? Should I update something? Please help!! Thank you!

Have you checked to see if it is compatible with Yosemite? http://www.wdc.com/en/products/products.aspx?id=420#Tab3