Today I was trying to copy some files from my external hard drive (1TB) to a flash drive (4GB) on Ubuntu 12.10. My flash drive contained an operating system, so I decided to format it using the disk management tool that comes with Ubuntu.

Unfortunately I ended up formating my external hard drive, and it was mounted. I formated it to FAT, and in the beginning it was NTFS. An error occurred (since it was mounted) and the label on the Hard Drive vanished, but I could still copy files from and to it. In the disk management tool the partition appeared as “unknown”.

When I saw the label was gone and that the partition was acknowledged as unknown, I knew that probably my computer wouldn't be able to recognize my hard drive partition once I disconnect it from my computer. Unfortunately I didn't have enough space to save all data from the hard drive to the computer it was connected to, so I did had to remove the hard drive to another computer: and what I expected happen – my partition is no longer recognized by Ubuntu.

Since I was able to copy files between the computer and the hard drive (I actually copied the files I wanted to my flash drive) before I remove it from my computer, I think there may be a way to recover my partition to its original state, and that's why I am creating this question. I have some data on the hard drive I REALLY NEED and that I don't have anywhere else. Any help would be appreciated.