Your WD My Passport fails to show up on your Mac due to few reasons. Check whether your USB cable and Mac computer are in good condition and make sure your USB cable is not broken. Sometimes, hardware problems can make your WD My Passport stop showing up on your Mac. If your problem persists, you can try the following steps.
Now, make use of the solutions given here to make your WD My Passport drive show up on your Mac.
Try the troubleshooting methods mentioned above. Now, your Mac should show your WD My Passport drive.