Or, maybe the easiest thing of all would be to just keep the 2TB plugged in as the "backup" OS drive, and just make the 4TB drive a pure data volume? Wipe it so there are no boot files at all and just ...
I found this site searching "Create bookable USB. It was a 4 year old topic. I did not have the Windows ISO file that was needed. I normally run Windows 8.1 Pro 64. But at times I need an older ...