Click noise on boot of My Book USB 3 external drive

I’m not sure when this issue stared. Maybe with latest os x update. 
When I boot my mac mini, I hear a " click, click, click " noise coming from USB 3.0 WD My Book 1140 Media ( description of disk utility ).

It happens the same thing if i disconnect power from disk, boot os x, and reconnect external disk.

After disk boots I don’t have any other issue. 

This is a Time Machine disk, no other files on it. 

I used disk utility repair from recovery but didn’t solve the issue.


There are many variables that could amount to a drive emitting unusual sounds when powered on. 

Please see if the following link helps.

How to tell if the noise or sound the drive is making is normal”:

seems like this is my case

“Clicking or clunking sounds that occur repeatedly”

i did remove the power cord but leave the USB cable connected 

seems that removing both power cord and USB cable solved the issue, at list for now

maybe with USB cable connect driver didn’t complitlypower off


I’m back after it seemed to be fix my disk stated the click noise on boot again

is not only for this noise but it slow down os x boot, because seems like os x waits a while for disk to boot before it complets it’s own boot

if i disconnect data cable and power on disk side, i leave USB 3 cable inside mac mini on boot it doesn’t do the click noise and boots 

if i disconnect data cable and connect to a windows pc it boots like on mac with click noise