So I finally got around to connecting the external hard drives that I had connected to my old 722. They all worked fine on the 722, but when I connected several of them to the Hopper with Sling I get the message that they need to be reformatted. Some of them connected and work fine, others say they need reformatting. I was hoping not to lose the data that is on those hard drives, is there anything else I can do? They are all WD drives, either 1TB or 2TB drives. Thanks for any information you may have.