If you’ve downloaded Windows 10 ISO image, here is how you can create a bootable Windows installer USB on Mac using UNetbootin.
UNetbootin is a free, open source utility that allows you to create bootable USB drives on Windows, Linux, and Mac OS X. Method 1: Create Windows 10 Bootable USB on Mac Using UNetbottin In this tutorial we’ll show you how to create Windows 10 bootable USB from ISO on Mac, by using the Terminal or third-party software like UNetbottin. How can I make a bootable Windows installation USB on Mac OS X? After upgrading to macOS Mojave, you may find that Boot Camp Assistant is no longer supported and thus creating a bootable USB turns out to be a little bit challenging.