tanveersml :
I m getting message when i plug the usb hard disk drive it giving message need to format i cnt format the drive becoase there is lot of data in the drive kindly help me in this regard.
This sometimes happens if you plug it into a different USB port than before. If this is the case, safely remove the drive, go into Device Manager, right click on 'Universal Serial Bus controllers' and select 'Scan for hardware changes'. This updates the USB hardware information. Then you can reconnect the drive and the system will load the drivers and the assigned drive letter should be the same.
This works for me with a 1TB USB drive with four partitions on it that map to drives D:, K:, L:, and N: If I change its USB port and rescan the USB hardware, the partitions stay correctly mapped to those drive letters.