More than 1 WD External Drive not fully recognized by Windows 7

WD External Drives External Drives for PC
1

External Hard Drives not fully recognized.

What should I do to get Windows 7 to fully recognize 3 Western Digital My Book External Hard Drives plugged into the USB Ports on my Sony Vaio Laptop?

Windows 7 shows them in the task bar, and I can see them in the Device Manager window, but they do not show up in Windows Explorer, and the Autoplay menu that usually comes up when you plug in a drive does not appear.

It used to be that I could plug in 3 external hard drives and they would all show up in Windows Explorer.  Now, only the first one will appear.

All of the drives work fine in all of the ports when I plug them in individually.  It is always the first drive that I plug in that is fully recognized by Windows, and the other 2 drives are only partially recognized.

When I plug drive A into the computer first and then drives B and C, they all show up in the device manager, but only drive A shows up in Windows Explorer.  The device manager says that Drive A is online, and Drives B and C are offline.

If I plug drive B into the computer first, and then drives A and C, they all show up in the device manager, but only drive B shows up in Windows Explorer.  The device manager says that Drive B is online, and Drives A and C are offline.

If I plug drive C into the computer first, and then drives A and B, they all show up in the device manager, but only drive C shows up in Windows Explorer.  The device manager says that Drive C is online, and Drives A and B are offline.

What do I need to do to get them to come online?

Thank-you for your help!

2

If all of these drives are the same size it may be a signature collision in Windows. This explaiins how to fix it http://community.wdc.com/t5/Other-Externals/Problems-with-having-more-than-one-USB-2-0-WD-2-TB-Elements/td-p/285724

Joe

3

I found the answer here.  Ayhan Dursan gave me the answer that solved my problem. 

He said, “Windows uses a unique identifier called a disk signature to tell one drive from another.  If both drives are the same make, size and type, chances are they will have the same disk signature.”  This makes it impossible to connect to of the same type of drive at the same time. 

He then gave easy to understand directions on how to change the drive signature.  I, along with several other people followed his instruections and now our computer sees all of the drives that we have plugged into it.