In some tutorials to use boot camp assistant, I see there is should be third option - create bootable USB drive from ISO.
Mine looks like this:
iMac 21.5 mid2011, Sierra 10.12.5
iMac, macOS Sierra (10.12.5)
I assume you have a Windows ISO from Microsoft Downloads. If it is not a mixed 32-bit/64-bit ISO, you can burn it to a DVD-R SL at the slowest speed and then use it to install Windows. Please be aware that W10 in not supported on 2011 Macs officially. W7/W8.1 are supported. You can upgrade to W10, if you want to, once W7/W8.1 is installed, by executing an in-place W10 upgrade.
Well, support page says bootcamp doesn't support only USB3.0 and USB C drives to boot from.
So I can just burn this same image on DVD instead?
I have Win8.1 x64 Pro image. Don't need latest version anyway, just like to test hardware with Unity engine and few games. For few weeks.
It should work. If you run into any issues with W8.1 installation.
Thanks.
Missing option to create a bootable drive from image?
