I have run into this same exact problem with Windows 8 and Windows 10. I used Rufus to create a bootable thumb drive. My computer boots from the thumb drive just fine and the Windows setup runs normally, until I get to the screen where I select which hard drive I want to install Windows on. Then I get an error message which says: "Cannot create a new partition or find an existing partition" BUT, if if take that same exact ISO and burn it onto a DVD, it installs just fine. No errors, everything works. What am I doing wrong?