Same problem for me. This happened when i tried to turn my hard disk upside down while transferring data.. it showed hard drive needs to be formatted.. I removed it and plugged it again but worked for some time again while transferring the window automatically closed and showed the formatting message again. What to do now? i've got about 1TB of data in that????
Actually, a couple months ago, my brother also experienced the same drive problems. The hard drive was asked to format after inserting to the computer and the inner data also became inaccessible. However, this hard drive had held most of his business files. How could he format it? Therefore, he did some researching over the internet, read may related articles and forums, and finally found a data recovery tool that eventually retrieved all his data back for free.
I remembered it had offered a special “format recovery” option for him to retrieve all his data back. Perhaps, it could also restore your data. Edit: Before you’ve restored all your data back, you should not write anything new on the same drive in case of data loss.