Yeah man - I followed your every word on it. I gave you a mention above. Cheers working great.
That is what I get for not reading every post! :-)
Great job!
The craziest part, and the bit I was kicking myself about after hours of head scratching.....
I was opening the CMD box , but not in administrator, and could not access \\.\PHYSICALDRIVEx what a dumbass...
But in the process I learned a shit load more than I intended to about MAME and CHD files.