Just to update that creating a bootable USB stick with Rufus done the trick, just make sure that 'GPT partition scheme for UEFI' is selected in the partition scheme type box. I was able to boot from UEFI and use diskpart to format the drive to GPT before installing windows. Worked like a dream.
Hi there, Got  a poweredge R710 with 6 x 2tb drives that I want to configure as 1 Raid 5 drive. I have managed to boot from Bios and install server 2012 R2, but this only allows a 2tb maximum due to it being MBR. I am unable to convert this to GPT due to only the one drive. I need to boot this from UEFI and install Windows, but I am having terrible trouble getting the USB to recognise. Does anyone have any guides on how to create a bootable USB that will work with UEFI? I have an ISO of server 2012 R2 I have tried to use the lifecycle controller, but this will not work as I do not have an optical drive configured and this will not go any further than the error saying one is not installed. We also do not have an IDRAC yet. Many thanks for any help.
Poweredge R710 Server 2012 Uefi boot USB