Can't see my external USB harddrive

I use several external USB harddrivs to backup my data. By copying my data to E:  (drive letter for external USB harddrive) every Friday. The computer is running Windows 7 professional.

But I recently bought a new external USB hardrive (same brand, size, western digital elements portable 500GB USB 2.0 ) and this new drive doesn't appear in the windows explorer window as the other disks do. I can see the disk in Disk Management and it hasn't got a driver letter assigned to it self.

I don't want to assign a driver letter to the disk. I want Windows to do this for me. As it does for
my other disks.

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kryloszConnect With a Mentor Commented:
Well Windows does is pretty stupid when it comes to handling USB drive letters. If you have one USB disk set as E:, unplug it, put in another USB device, assign it to E: and plug in the other disk, it will not assign it a new drive letter. That's what the tool I posted above does. Try it.
In Disk Management right click the external drive, and make a partition/assign it a letter/format it as these are the propable causes.
how long is the cable?  try a shorter USB 2.0 cable. It has to do with voltage drop recived to and from the port.
Ernie BeekExpertCommented:
If windows doesn't do it, you have to do it yourself as andreizz said. You only have to do that once. After that windows will remember the drive assignement.
Yes, you need to do this yourself, I don't exactly know why, but for some devices windows will not asign automaticly a drive letter (and I don't think that the length of the cable has anything to do with it) . As Wizard said, you only need to do it once, after that, the drive letter will be assigned automaticly every time (or until you will reinstal the operating system).
Right click on command prompt- select run as administrator-In command prompt type  diskpart and hit enter.

Then type the command -> automount enable       --and then hit enter.


Windows XP sometimes has problems assigning drive letters to USB disks. You could and should try this tool, it should fix your problems.

In Disk Management what is the partition type that's listed for that drive?
If the drive isn't partitioned or formatted Windows won't give it a drive letter.
Since it is a new drive, I suggest you format and partition the drive.
JasonMewesAuthor Commented:
ok, I have tried this
1. assign the disk a letter
2. formate it
3. i can see and access the disk
4. unpluged the disk
5. pluged in one of my old disks (that used to work fine)
6. can't see the old disk now
7. unpluged the old disk
8. pluged in one of my other old disks (that used to work fine)
9. can't see the old disk now
10. assigned the old disk a driver letter
11. i can see and access the old disk
12. unpluged the old disk
13. pluged in one of my new disk
14. can't see the new disk now

the usb cable is about 10 inch and is connected direktly to the computer (no usb hub)
Try to reinstall your chipset/motherboad latest drivers, maybe the usb drivers are a bit "dumb" and don't know how to controll you usb devices properly..

Also if you can try and use another rack with your hdd's.
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