The disk file system is likely corrupted, and Windows is having trouble reading it.
I take it that you wish to:
- Retrieve data from the external hard drive ... and then ...
- Format it to be able to use it normally once again.
Is that correct?
Data recovery from a difficult situation (for example a failing hard drive or badly corrupted disk file system) is best done with the ailing hard drive attached directly to a computer's motherboard, rather than attached via USB connection. The USB connection is susceptible to data corruption and limits "readability".
If possible, connect the ailing hard drive directly to the motherboard of a desktop PC ("internal" secondary) and try the following suggestions. The first suggestion is to try booting from a Linux CD or flashdrive to see whether or not you can see and access your files, and simply copy them to an external USB hard drive or flashdrive (or another internal hard drive). This may not be possible: If that is the case, then the second suggestion is to attempt data recovery using TestDisk, again run from a bootable Linux CD or flashdrive.
If it is not possible for you to connect the ailing hard drive directly to a PC, then you can try accessing and copying the data while it is connected via USB, but the chances of success are somewhat less.
I will post instructions for you to try the first part of the suggestion, assuming you have the problematic hard drive connected directly to the motherboard of your desktop PC. Let me know what happens.
(Note: Instructions were written for the situation where the ailing hard drive is the one containing the operating system, where the computer is no longer bootable and the files need to be recovered. Hence the "working computer" and the "ailing computer" references. In this case, the files are being copied to an external hard drive or flashdrive.) Please adapt the instructions to your own particular circumstance.Suggestion 1: Use a LIVE Linux operating system run from a bootable CD or flashdrive to access and copy/retrieve files on the hard drive to a USB-connected flashdrive or external hard drive.
There are many options, but here are detailed instructions for one method ...
to the desktop of your working computer
You will use this CD to boot the ailing computer from.Backup your important files to an external media using xPUD:
- Run GETxPUD.exe
- A new folder will appear on the desktop.
- Open the GETxPUD folder and click on get&burn.bat
- The program will download xpud_0.9.2.iso, and when finished will open BurnCDCC ready to burn the image.
Please be patient: This could take awhile - download file size 63MB.
- Click on Start and follow the prompts to burn the image to a CD.
To shut down the computer:
- Connect your external hard drive or flashdrive.
- Boot the ailing computer to the xPUD CD.
A Welcome to xPUD screen will appear.
- Click on File.
- Expand the mnt icon on the left (click on the little arrow beside the icon).
- sda1, sda2 etc. ...usually correspond to your HDD partitions
- sdb1, sdc1 is likely to correspond to a USB flashdrive, external USB hard drive etc.
- Copy your important files to an external hard drive or flashdrive.
- Open your hard drive partition and navigate to the files/folders that you wish to copy.
- Select multiple files/folders by holding down the <CTRL> key and selecting them all.
- Use right-click > Copy
- Navigate to your external media, and in the right-side window pane, use right-click > Paste.