What should I do? Refered to my hard disk

Hey, I have a Seagate Expansion Hardisk and when i plug into my mac it opens the Disk Utility and it appears that the partition scheme map its unformatted. And when i try to erase all the content, or create a new partition i can't it appears that fail.What should I do? Its ok if I lose my data, but I just want to use my hard disk, if exist an option that I wont lose all the data, I would prefer.