It could be a driver or OS issue but I don't see enough detail to start any discussion about that.
How about a test in Linux? Here I could boot my Ubuntu CD (no install!) and see how a copy works there.
Bob
I have a couple of portable external HDDs. One is 1.5TB WD Element (has a separate power input), and another is 250GB WD My Passport (draws power from my USB 2.0).

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