Windows Images not bootable when made with ImageUSB

[geeham]

Thought I would give this a try instead of my usual rufus which ive used before to burn windows iso usbs but although it worked and put the files on it didnt show as a valid boot device but did when done with rufus.

Any ideas why this may have happened or ways i can try and diagnose?

[David (PassMark)]

Which version of Windows ISO?
Which version ImageUSB?
What size USB flash drive?