Hi

I am having issues with external hard drives. I have 2 WD External Hard Drives (1 TB Each) the problem is I can only use one at a time, My Laptop has 4 usb ports. Both Hard drives work actually but it only recognize one hard drive when I plug them at the same time.

Please Help. Thanks

Have you assigned them different drive letters?  You would use diskmgmt.msc to do this, one at a time, so that they'll have different drive letters when you have them both plugged-in.

Try listing volumes with diskpart and mounvol like:

C:\Windows\System32>diskpart
DISKPART> list vol

This will show all volumes in your system and logical drive letters assigned to them.

Judge what's your 2nd WD drive that's not showing in Windows Explorer by the Size column.

If a volume does not have an assigned drive letter, run

DISKPART> sel vol n
DISKPART> assign letter=NEWLETTER

Where n is the volume number displayed in the Volume ### column of the list vol output, and NEWLETTER is the letter you want to assign to your partition that is not showing in Windows Explorer.

If you don NOT know drive letter of a desired volume and do not want to assign a drive letter, you can access volumes without doing it just by knowing their GUIDs.

Type exit to quit from diskpart if you have DISKPART> at your command prompt and run

C:\Windows\System32>mountvol

to display GUIDs of all volume guid present in your PC. Those volumes that are listed as

*** NO MOUNT POINTS ***

are those that do not have any drive letter assigned to them.

Copy their GUID address such as

\\?\Volume{96402ff0-d0db-4f20-9293-15dde9c202f6}\

and paste into the Run dialog box (press WindowsKey+R to open it), then hit Enter to display the content of this volume in Windows Explorer.

dude you should try bringing the second ext HDD into online mode through device management

step -1 right click on my computer

step-2 select device/computer management

step-3 go to the problem HDD/partition and make it online

problem solved

I am having the same problem.  I just bought a 2TB WD MY BOOK desktop EX-HD and would like to buy another WD MY PASSPORT USB EX-HD which has the same password protection software as my MY BOOK.  The online research I've done is some what conflicting, on one hand some people say it would never work having the same software, others say it does work with their computer. 

Please be patient with me as I am a complete novice at all this (technology) but what does step-3 mean?  What is online mode and how do I go about trying this, and most of all would my files be safe?  It's the on-line bit that worry's me.