To recover the lost 2TB data, you’d better firstly try a hard drive recovery freeware
and then format it to have a try. This freeware has helped my friend retrieve all his inaccessible data from a “not formatted” flash drive. I believe it will help you, too.
If you are interested in it, you can visit here: -http://blog4mark.blogspot.com/2012/11/convert-raw-to-ntfs-without-data-loss.html
The “not formatted” problem often happens because of improper use, virus attack, or even weak power support, etc. Don’t worry!Note
: You should never store new data on this drive to rewrite the original data.
You should never store you important files on only one hard drive.