Windows 7 - Can't access external HDD?!

Hello,
When i connected my 4TB WD external HDD to my computer via USB,
this is what shows in My Computer:-


It's nearly FULL, but it says that it's empty & can't access it:-

This the Device Manager:-

This is the result after almost 9 hours of Checking Desk in CMD:-

it only reached 10 Percent, & i am sure that my files is much more than 142320!
also notice that the Volume Lapel is: "4 TeRa A", which is not right, the right
Lapel is: "4 TeRa B", i have another HDD called "4 TeRa A", but i didn't connected
this HDD in days! & never connect both of them together! What GIVES!

PLEASE HELP!

Is there data on that hard drive that you need to save? If so, do not do any procedure mentioned here or elsewhere until you have backed up that data! Many procedures will erase the data on the drive.

What it looks like is that the external drive has been formatted in the new(er) GPT format for EFI system disks. This is necessary with such a big drive because the old MBR file system can't deal with it. (also note that it shows the drive as FULL - all blue).

I do not have and have not been able to play with GPT disks. So I don't have any pointers right now. I am sure someone will be along shortly who does have experience with these disks, so be patient.

And be very sure about what you are doing before changing anything!

Were you using this external drive on another PC and now you are trying to access it on a different system? Or did something change in an existing setup?

More info: http://en.wikipedia.org/wiki/GUID_Partition_Table

Have you checked WD website for any issues you're describing? What is the make and model of the external HDD?

thank you for your response.

1. i used it on same pc, & didn't change anything in the system.
2. i have already tried WD community, but nothing helped ( the pictures ).
3. WD My Book Studio Edition II, S/N: WU2Q10253418.

PS: notice that the Volume Lapel in CMD is: "4 TeRa A",
which is not right, the right Lapel is: "4 TeRa B",
i have another HDD called "4 TeRa A", but i didn't
connected this HDD in days! & never connect both
of them together! What GIVES!

Follow Up:
We would need to know some more clues to make sense of this problem. Can you think of anything that could have changed on either the system or the external drive that might be a potential cause of the sudden non-recognition?

Have you tried shutting down the (Laptop? Desktop?), disconnecting the external drive, restarting the PC, then reconnecting the drive?

Can you "Safely Remove Hardware" when the drive is plugged in?

More info on Windows 7 and GPT disks here:
Windows and GPT FAQ

Another thing: external drives that get all their power from the PC's USB port can be quite finicky.

• Try another USB port
• Try with Laptop's power adapter plugged in
• jiggle the USB cable in the USB port

thank you for your reply,
1. when the problem occurred, i haven't connect this HDD for over a month.
2. i tried several ports, cables & computers.
3. this HDD have it's own power supply.
4. there is no icon in status bar, so i can' "Safely Remove Hardware"!
PS: new update sense i tried to connect it just know:-
it's even doesn't appear in My Computer nor Device Manager.

If it will not show up on other computers, does not get recognized by the system when plugged in, you've tried other data cables and ports, and does not show up in your list of drives then that pretty much points to a failed drive.

Keep in mind that GPT formatted disks only show up in modern operating systems, and IIRC an external (removable) will only be seen in 64 bit systems.

If all of the above is indeed true, then your next step will be to (assuming it is not still on warranty) pull the drive out of the external shell and connect it directly to the PC internally using a SATA power connector from your power supply and a new SATA data cable. Then test it.

Be sure you have the proper connections and cables before you pull it apart.
Be sure to shut down the PC before making connections.
You should be comfortable with doing this, and have some knowledge and plan for how you will reassemble the unit and then work on the USB connectivity issue (assuming it is a working drive).

If not comfortable then bring it to a shop. They can test it and maybe even repair it.

i tried to do something similar to what you told me:-
i opened both of HDD Cases which i have ( the working
& non-working one, which are both exactly same specs )
i changed the HDD between them:-
1. Put working HHD, in non-working case.
2. Put non-working HDD, in working case.
& in both scenarios DIDN'T working, but:-
in case 2: what happened to me is the same as
post #1, So what i get here that the case &
HDD have some problem, which was fixed when
i changed the case, & BACK to the HDD problem!!!!

Hello again,
is there a way to change the format of this HDD WITHOUT erasing the data?
or is there a guaranteed way to restore all of my data after the format?
because i have noticed using PARAGON HardDisk Manager that there
is no format of this HDD in the first place < that's why the PC
can't read it or do any thing to it!

No! Formatting means you are deleting everything and starting with a fresh, empty drive. So does initiating.

(Technically the data remains but the FILE SYSTEM sees the entire drive as empty)

Try this: in Disk Management, right click on the drive and assign it a new drive letter. See if that changes anything.