Hyper-v 2012 R2 error

[harryw]

Hi.
When installing the official Hyper-V Server 2012 R2 image I get the following error right at the end of the 'build' process;
'Failed to run system API.(0x0003001501D00000)'
I have tried this on a WD 2500BEV External 250Gb and a Sandisk Slimfit 16Gb with the same results.
I have also used a Windows 8.1 image with no issue on the WD external drive.
I am running the WinToUSB program as administrator on a Win 8.1 Pro with Media Centre system.

Any idea's ?

Regards,

Harry W.