I have WD "my passport " hard disk and these day it dosen't work or appear in my mac and dosen't appear in disk Uitility either . I don't know the reason by the way it works in other MAC laptop.
MacBook Pro, OS X Mountain Lion (10.8.3)
Hi, is it USB or Firewire?
reset FW bus, same goes for USB reset...
Reset the Firewire bus
If your Firewire or USB isn't recognizing any device. A solution which has worked for some whose hard drive became invisible in 10.4 was simply to follow these four steps to reset the Firewire/USB bus:
1. Shut the machine down.
2. UNPLUG the power lead to the computer and any firewire/USB drive or devices.
3. leave it for 10 minutes.
4. Connect back up and reboot.
It is USB
I did it but didn't work
Try the usual things to throw at this.
PRAM reset
http://support.apple.com/kb/HT1379?viewlocale=en_US
SMC reset
External Hard dosen't work .
