Try this solution which was presented by ranis in the My Passport for Mac isn’t recognised posting.
There is “wd drive utility” software that would launch upon start up that creates the problem, go here to delete it:
FINDER - GO - COMPUTER - LIBRARY - LaunchDaemons - com.wdc.WDPrivilegedHelper.plist
DELETE THAT FILE
Then, go to
SYSTEM PREFERENCES - USERS & GROUPS - LOGIN ITEMS - UNCHECK WD DRIVE UTILITY
Restart your comp.
If the above does not work out for you strongly suggest that you research the forum if you have not already done so and/or call WD tech support for a solution if you are still under warranty.
Sorry, I am fresh out of ideas. GOOD LUCK!!!
