Windows 7 - "A required CD/DVD driver is missing" during USB Install

Encountered a strange error earlier today while installing Windows 7 x64 using a USB stick rather than physical media, the installer failed with 'A required CD/DVD driver is missing'

I had just built the USB installer from an official Microsoft ISO using the Rufus tool and did not expect to encounter this error.

The solution was very simple, instead of using a USB 3 port on my computer I connected the USB key to a USB2 port (my ESATA port doubles as USB 2.0 port) and this resolved the issue.

Happy days!