I'm not familiar with this drive, but their web site is awful. There's no documentation on this or similar drives. It's a very new drive - appears to have been released in August 2010. Have you called their tech support for help?
What I was able to find was that this drive requires a "Y" USB cable, meaning you need a cable with two male "A" plugs; one for conventional USB 2.0 and one male "A" plug for power alone. I presume you're using the cable provided with the drive. If not, get one... Try Cables To Go or a similar site.
> Try removing all other USB devices except keyboard and mouse.
> Reboot the PC with the device attached to the back of the machine - not through a hub and only using OEM USB ports.
> I'm assuming because it works on XP, the cable is good. But I would try a different cable anyway or try moving the two A plugs to different USB ports to rule out faulty USB ports on your PC.
> Try hooking it up to another Win7 box.
Other than that, don't know what to tell you without a lot more detail.
...this drive requires a "Y" USB cable, meaning you need a cable with two male "A" plugs; one for conventional USB 2.0 and one male "A" plug for power alone. I presume you're using the cable provided with the drive. If not, get one...
For those with drives having no external power supply (i.e., Bus Powered Devices): I really suspect this is a USB bus power problem or maybe those of us experiencing this have bad USB cables, but can't understand why Win7 seems to be the lowest common denominator. It sure is bugging me.
One alternative to the "Y" cable will require a little searching, but look for USB cables that that have 20 AWG to 24 AWG sized power wires. Most are 28 AWG (in the case of wiring, the smaller the AWG, the greater the diameter of the wire core and the greater its ability to carry higher current). Sometimes you'll see these advertised as "Extreme Power" USB cables. The full spec for the wire itself used in one Extreme Power USB cable I own is:
"E300060 AWM 2725 60C 30V VW-1 CSA LL204790 I/II A 80C 30V FT1 MSL"
Another common way they are identified is the size of the signal wires/size of power wires... depicted as: 28/20 or 28/24 or 28/28 (sometimes the numbers are reversed). Again, a lower AWG rating is better. Here's a very good one: USBgear.com
I had the same problem with a WD Elements external hard drive, where the system would not see the hard drive or if it did, said it needed formatting. On my old XP computer I was able to see the hard drive and make it work OK. I read in another forum that one guy solved the problem by replacing the original USB cable with a 6" cable. This prompted me to try another USB port, so I tried a port on a powered USB hub on the back of my computer (that is, a hub with a separate DC power input) and the hard drive worked fine. Solved. I think bezimmer's comments are right on.
In my case I had to plug in all 3 plugs of my USB cable. My enclosure came with a cable with 3 plugs as shown here External IDE 2.5" Enclosure USB 2.0 Hard Disk Drive HDD - eBay (item 130393322344 end time Oct-18-10 06:48:57 PDT). I plugged in only one plug and the red light on the enclosure turned on but there neither windows 7 nor vista displayed the hard drive in either explorer or disk management. I plugged in the second USB plug into another USB port and immediately Windows 7 and Vista installed device driver software and i was able to access this drive. I guess it is a matter of one usb port not being able to provide enough power.
The WD externals have turned to crap. They built in a virtual CD that cannot be deleted. Their Smartware is total crap. They use a micro USB plug that many have problems with becoming loose. A lot of people that did the last firmware update wound up with corrupt data. From what I can see it was a problem from the beginning and they just stuck on more and more of their drives and thummed their noses at customers. Customer Service seems to be nearly nonexistent. I had a My Book Pro and an Essential without the mess and no problems. Relying on past experience I stupidly got one of the new Essentials with Smartware. The only smart person in that disaster is the guy that sold them the Smartware. I think the only model left that is a plain plug and play drive is Elements and that has the chintzy USB port too and is only USB 2. When I need another external I think I'll look into building my own.
Re: Western Digital External Harddrive problem SOLVED
If you have an External WD Desktop Hardrive: My Book Essential, and it will not work on Windows 7 try turning it off, plugging it into the computer or laptop and then unplugging the power cord from the device, wait a few seconds then plug it back it, this will make the device recognize the computer which hopefully will solve you problem, because for this one in particular there is no driver to download from WesternDigital's site.
Re: Western Digital External Harddrive problem SOLVED
click on start - type cmd - do not press enter.
right click on the command window icon and choose 'run as Adminstrator'
in command, type diskpart. When diskpart has started, you can type help to access the commands and exit to leave. Be careful with this tool
type list disk - your disk should be listed. if it isn't then unplug the usb connector and then reconnect it and then type rescan.
When you can see your disk and assuming it is listed as disk 8
type select disk 8
then type list volume.
you should now be able to see a list of volumes. Note which volume is the one that is the same size as the disk that you want to view/mount and note its number. for instance, the volume that you want is volume 7.
type select volume 7 (make sure to change the number to the volume that you want).
This volume will be the one without a letter next to it like c: d: etc.
The volume should be assigned a drive letter. type exit. then type exit to leave the command window.
Your drive should now be available in windows explorer.