HDS723030ALA640 is 3TB and shows up as 854GB

Right-click on "My Computer"
Click "Manage"

Double-click "Disk Management"
You will probably see Disk 0 and Disk 1 for your primary hard drive.


Go to lower right portion of box and scroll down until you see Disk 2. It is probably your USB drive without a letter. It should show the size of the drive.


Right-click in the left portion of that drive box (Disk 2)
Click "Initialize" and "OK" in the next dialog box. This takes just a few seconds and it should now say "Online" in the "Disk 2" box.


Right-click in the box to the right side of the "Disk 2" box (where it shows your disk drive size and says "Unallocated".
Click "New Partition" and a "New Partition Wizard" will open up.


Click "Next", then select "Primary Partition" and click "Next".
Verify partition size (use entire disk size available unless you are creating multiple drives) and Click "Next".


Assign drive letter ("F" is typical if CD-Rom is E) and click "Next".
Format this partition with "NTFS", "Default", "New Volume" and click "Next".


Then click "Finish" to exit the wizard and start formatting.
Be patient... this can take awhile (it took just over an hour for a 320GB drive).
When done, you should see an icon for your drive in Windows Explorer!


hope this helps

Even though the drive may not be visible on the Desktop or in My Computer check to see if the drive is recognized in Disk Management

Right click on My Computer and select Manage from the menu From the Computer Management window select Disk Management from the menu on the left

In Disk Management check to see if the drive is visible

If the drive is found look at the partition for the drive

New drives will be labelled as FAT32 and have a drive letter assigned

If the drive does not display as Healthy or shows the file format as RAW then the partition has become corrupt

It could also be corrupt if the bar above the drive is black and shows as Unallocated

To make the drive usable again after a partition has become corrupt or lost start by right clicking on the drive in Disk Management and select Delete partition from the menu

Then right click on the drive again and select create partition from the menu

Follow the steps in the partition wizard to create a Primary partition

NOTE: Deleting the partition will cause all data on the drive to be lost. If the partition has become corrupt this may be unavoidable

Hitachi Global Storage Technologies is not responsible for lost data

It is highly recommended that data be backed up in multiple locations on multiple drives to minimize data loss
After the new primary partition has been created Disk Management will display the drive with an NTFS partition

The NTFS partition is unusable on a Mac. If the drive is used on Macintosh and Windows computers follow the link below to obtain a FAT32 formatting tool which will allow both Windows and Macintosh users to use the drive

hope it helps

Using Disk Management Utility

Disk management utility will help you see all the drives that are connected to your computer, including internal hard drives, CD or DVD Drives, and removable storage like USB sticks and external hard drives. Using this utility, you can check for attached drives that are not visible in windows when attached to your computer. You can also format drives, change drive letters, mark a partition as active and delete partitions. A word on caution about using the Disk Management Utility: This utility can cause destruction of data. If you are not sure of what you are looking at and uncomfortable with using this utility you should consult with an advanced user before making any changes to drives using this utility.

The Disk Management utility can be accessed in two different ways.

#1- You can open the Control Panel,

Click on Administrative Tools,

Click on Computer Management and the Computer Management window will open.

#2- Right click on you "My Computer" Icon

A menu will open

Chose "Manage"

The Computer Management window will open

The Computer Management window is broken down into 3 sections.

The first section on the left side of the window shows a menu. Disk Management is on the lower portion of the menu.

The right side is separated into two sections, top and bottom. The top portion shows a list of active drives on the computer. The lower portion shows all drives connected to the computer. CD or DVD drives that have not disk will not show as active drives on the top section, but can be seen in the lower section.

The lower section will show the drive description, drive size and drive condition (online or off line) in small box on the left side of that section. Disk drives will designate a "Drive" and a number. Drive 0 is usually your internal hard drive. Then it would list drive 1, drive 2, etc, depending on how many internal and external drive sources you have connected to your computer. Then it will list your CD drives and generally show their drive letter assignments.

Next to the smaller section described above, is a larger section which shows the driver letter, size of the driver and condition (if working correctly will show "healthy")

This is the area you can right click and get a menu that will allow you to open, explore, mark the partition as active, change the driver letter, format the drive or delete a partition. (A note of caution here. Changing the driver letter on your main hard drive partition will cause windows to stop functioning. The main hard drive, or hard drive partition, is normally given the letter "C".) A hard drive may show two or more partitions with separate drive letters designated for each partition.

A drive this is having a problem may show that it needs to be formatted (status as Unformatted). This can be done from this window. An external drive, whether it is a hard drive or CD/DVD drive, can have the letter designator change done if you want to organize your external drives. There are times when a drive will not show up because the drive letter that they are programmed to use are taken. Most USB drives are programmed to us the letters "F" or "G". In this area, you can assign the USB drive any drive letter that is not being used and this will make it visible in windows.