Win 10 USB install error, "...cannot create or find existing partition."
Issue resolved!! Attempted to once again copy Win10 setup files to HDD but it still wouldn't boot. All of the instructions on resolving through cmd prompt were flawed as they instruct you to create a MBR instead of a GPT which will work on older bios machines but it must be GPT on UEFI boot machines. Going through the process did give me an idea tho' so I deleted all partitions on the HDD and left the space "unallocated". Sure enough the Win10 setup on USB worked. Hope this helps someone else.