Trying to install W10 to a Samsung 850 EVO SSD on my Ultra. At the "Where do you want to install Windows" screen I can see the SSD as Drive 0 partition 1. It shows the correct total size and is Primary. Whatever I do Windows throws a "We couldn't create a new partition or locate an existing one" error. I've tried deleting the partition and letting W10 create it. I've tried formatting the partition. I even ran diskpart and set up the partition at the command prompt. I can copy files to the SSD when it is formatted, from the command prompt, so I can't see that there is a driver problem. I also tried setting up a partition on the eMMC drive. Again, I can read/write it from the command prompt but W10 won't install to it. So I think this issue is not specific to the SSD. I don't think I have ever got stuck here before! Grateful for any ideas anyone might have.