I have a similar problem. I am using a WD My Passport for Mac 1TB HD with my MacBook Air. I configured this HD for Time Machine and worked fine for a while. Then, suddenly, it is not recognized by Finder. I ran WD Drive Utilities and this software is able to find it. The SMART status diagnostic passes with no problem.

Hi; I have 2 TB WD MyPassport Ultra external drive. It was working fine the last time I used (few weeks ago) but now it wont show up on either PC or Macbook I own. The light on the drive is illuminated (not blinking). The drive's vibration is too weak to notice. Visuak studio for mac. It is showing up on device manager as well as bottom right icon bar of the Windows. For info: I am using Windows 10 on PC & OS El-Capitan on Mac. I have tried changing the cord.

It doesn't work. Other external drives I own work fine. Tried updating the drivers & it did not work. I am desperate it.

(Let me add that I am not a computer expert so any advice should be simplistic, please). When will we get high sierra update for mac.