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momodedeaux, Thank you very much for joining the Intel® NUC communities and for providing that information.
Most of the times when this problem happens is because the ISO image of Windows® 7 is not working properly, I had that same situation and the problem was because of the image. So, please try to create a new ISO image if it is possible from the disc itself:
Once you to that, try to run the Windows® 7 USB 3.0 Creator Utility again, and if it is possible please use a PC that is working with Windows® 8.1 to use the utility, because when we followed this process in our lab it worked fine every time with Windows® 8.1. If you do not have that option then you can use Windows® 10, it should work that way as well.
Please let me know the results of trying the steps above.
Any further questions, please let me know.