In these day external hard disks are very common. The storage capacity of the external hard disk is increasing day by day. By adapting the latest USB standard, the data transfer become fastest and easy. The price of the external hard disk is dropping. we get a more capacity hard disk, If one is ready to wait for a short time. Most of the people use external hard disk to store multimedia data, personal data, office data, some times some confidential data. What ever it may be it can easily access from any device, that support a usb connection. There is no doubt that external hard disk is the most convenient way to share or transfer big files between PCs.

But external hard disk is not free from errors. A lot of users complained about their external hard disk is not showing up. I know this is a common issue with external hard drives. The external hard disk may appears in the disk management, and some times the external hard disk may shows as ‘unallocated’ ! Most of the time the disk may contains your valuable information. Most of the time online discussion forum suggests a ‘Format’. But it is not advisable if it contains data which you want to keep. some people advice to go for ‘advanced NTFS recovery tools’ which may cost a few dollars. But it may not give the satisfactory results all the time. Believe me, I had faced a similar problem with Seagate GoFlex 500GB external hard disk. On a day it is suddenly showing up that the disk is unallocated. I checked it in the ‘disk management’, there it is showing as unallocated. Some people suggest that, if you need to recover data from it, it would be best to take your external HDD to the nearest local hardware repair it !

No, you don’t want to rush to the nearest computer shop to fix this technical issue. Most of the time the issue is due to overlapped/error in partition table.  To solve this issue first check the hard disk is showing in the disk management. To access the disk management,


Method 1 : Assigning Drive Letter

Connect your external hard disk to the computer. Then open the ‘disk management’.

To open disk management in Windows 7

Click  ‘Start button’ and  select ‘Control Panel’. Then click on the ‘System and Security link’ (If you are viewing icon view of Control Panel, click on the Administrative Tools icon). In ‘System and Security window’, click ‘Administrative Tools heading’ located near the bottom of the window. In Administrative Tools window, double-click on ‘Computer Management’ icon. Then Computer Management opens up, click on ‘Disk Management’ on the left side of the window.

Short cut:- Click ‘Start’ button, type “diskmgmt.msc” and press ‘Enter’ button. Another way is, right click ‘Computer’ icon in the desktop. In the popup menu click ‘Manage’. The computer management window is open up. Click ‘Disk management’ under ‘Storage’.

To open disk management in Windows 8

First, swipe up to open the Apps screen. If mouse or stylus is using, click on the arrow icon at the bottom of the screen instead. On the Apps screen, scroll or swipe toward the right and locate Windows System. Click on or touch Control Panel, located under the Windows System category. Control Panel is opened up. Click on or touch the System and Security link (If you are viewing icon view of Control Panel, click on the Administrative Tools icon). In the System and Security window, click or touch the Administrative Tools heading, located at or near the bottom of the screen. In the Administrative Tools, double-tap or double-click on Computer Management. In the Computer Management, click or touch Disk Management, located on the left-hand side of the Computer Management window.

In the disk management window, click on the external hard disk and right click. A popup window is displayed. click “Change drive letter and paths..”. You can ‘add’ or ‘change’ the drive letter here. Once you maid the change the external hard disk is automatically showing up.

Some times the external hard disk may appears in the disk management and may be displayed as ‘Unallocated’. There on right clicking you cannot see the “Change drive letter and paths..” as enabled. In this case a detailed checking may show that the partition table is overlapped or having some error in partition table. Here the things become more complicated to solve. Don’t worry just do the following steps.

Method 2 : Repairing the Partition table

If the drive or partition shows up in Device Manager and Disk management, but not in “My Computer”, there is a chance for missing or corrupt partition table.  To solve this problem, you need a freeware program, TestDisk to repair the partition table and get access to your data again. There are two places where we store file system information: the MBR partition Table and Volumes boot sector, when the file system information provided on these two sectors of disk is not good you may see chkdsk reporting raw file system. Don’t worry, TestDisk will not change or delete any of your data if you are following the instructions as explained below.

First download TestDisk from

The downloaded file is a compressed one, Unzip the downloaded file to your hard disk and Open  the uncompressed folder and search for ‘testdisk_win’ application in the folder and double click the “testdisk_win” icon.

The program will opens up and runs in a command window. Follow the steps from 1 to 10.

Step 1: In the first window, select ‘No Log’ (use down arrow key to select) and press the Enter key.


Step 2: Select the drive to analyse (select your external hard disk using arrow key), choose “Proceed” and press the Enter key.


Step 3 : Select partition type. If you are using a PC, select Intel and press the Enter key.


Step 4: Select “Analyse” and press the Enter key. The drive or partition will be analysed.


Step 5: Select “Quick Search” at the next screen, then press the Enter key.


Step 6: Enter“Y” if the partitions were created under Vista – “N” if not.

Step 7:  TestDisk will show “Structure OK”. Choose the drive or partition to fix and press the Enter key.


Step 8: Select “Write” and press the Enter key.


Step 9: Enter “Y” (press ‘y’ button in the keyboard).

Step 10: Press  Enter key and close TestDisk.  Now reboot your computer.


TestDisk displays You have to restart your Computer to access your data so press Enter at the last screen, keep the external hard disk connection and reboot your computer. After rebooting the computer, the external hard disk will automatically displayed.

Did these steps solved your problem? If not please let me know. I think this is the best method to restore or repair a corrupted partition without loosing the data. You can read the Testdisk usage help from here.


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