I purchased the 1 TB Backup Plus Portable Slim External Drive. It works just fine with my Mac. I've tried 3 separate Windows machines now, a brand new Lenovo, an older Sony Vaio, and a year old Dell, and this driver absolutely refuses to install on ANY of those Windows machines (2 Windows 7, and 1 Windows 10). I used it on the Mac first, but it's maybe 2 months old now and has less than 10% used. It gave me the exact same issue on all 3 of the Windows machines, it will not recognize the device AT all, I can see it in there, when I look in Disk Management, but there is not any letter assigned to it, and if I attempt to right click and format or do anything to the device, everything is greyed out. I cannot access the files on the drive, and if I attempt to update the driver, it tells me Windows has already allocated the best driver for the device. I don't really feel like reformatting it, that would completely defeat the purpose to me. If I'm going to have to back up that entire drive somewhere else, I might as well just have to purchase another one and have 2 of them, one for the Mac and one for the Windows machine. And Seagate should disclose that the external drive is only compatible with ONE O/S or the other...not with both. :-/
Oh, and I DID contact Seagate, registered my product with them and everything, and that's a serious waste of time. They make it almost impossible to get through to their customer service, and if you do manage to get through to someone, they don't bother to read anything that you write in your trouble ticket. You have to pay to be able to resolve anything to speak with someone on the phone. They do offer to attempt to solve it with you over e-mail, but it would be a very tedious process and the e-mail response team isn't capable of anything beyond a level One support.
Oh, and I DID contact Seagate, registered my product with them and everything, and that's a serious waste of time. They make it almost impossible to get through to their customer service, and if you do manage to get through to someone, they don't bother to read anything that you write in your trouble ticket. You have to pay to be able to resolve anything to speak with someone on the phone. They do offer to attempt to solve it with you over e-mail, but it would be a very tedious process and the e-mail response team isn't capable of anything beyond a level One support.