I just bought this Western Digital My Passport Essential 500GB External USB 2.0 / 3.0 500 GB Hard Drive, and am getting the same issue with Windows XP SP3. Initially, the computer recognized the drive, and allowed me to install the Smartware software. I was also able to set a protection password and copy some files for testing. The second time I tried to connect the external drive, it would crash my system. This continues to happen even after I uninstalled the Smartware software. Unbelievable!

SOURCE: External hard drive not recognized

I recenctly bought a my book 500 gig drive and it is usb.
the firsttime I plugged the usb cable in it worksed. I had only a 40 gig ide harddrive and so I ordered an internal 500 wd hard drive to replace it. The internal 500 gig is a sata drive. first I cloned the 40 to the sata 500 and then copied the external 500 to the internal. I mover the cables to then make the internal 500 sata my boot drive. The computer would no longer show the external e\when i used the windows explorer. the device manager said it was there and working with no problem but windows did not see it.
After several experiments with diferent configurations I have concluded my motherboard wasauto configuring the external and internal 500 drives as drive 0. Since the usb was detected first and was notthe boot drive then windows assigned the internal drive as drive 0 and since the usb drive was drive 0 also it would not work. windows ignored it. my solution was to return the ide as the boot drive and plug the sata into a slave port. with that configuration both drive are seen and work normally. It took me several days to find this arrangement. so since my sata ports are auto configure and the external has a sata connection i will install an esata port adapter and try to hook it up as a slave sata drive so i cab\n use my internal 500 sata drive as my boot drive.
sorry this was so long but it is my solution to what others may be facing.

SOURCE: XP doesn't recognize my external 500 GB WD My book essential edition hard drive

I had the same problem some have posted about. I had a lot of data on my drive and then one day it didn't show up in "My Computer" anymore. I had to assign a separate drive letter to the external drive.

Plug in the drive.
Right click on "My Computer"
Click on "Manage
Click on "Disk Management"
On the bottom half of the right side you should find "My Book" assigned to a disk number.
Right click on "My Book"
Click "Change Drive Letter and Paths"
Click Change
Select a new drive letter and hit OK

Hope this helps some people out.

SOURCE: how unlock the wd smartware my passport

forgot my password