Issue with my WiiU

[Gold Ranger]

I'm having an issue with it.
When I download a game to the External Western Digital 2TB Hard Drive, I keep getting an error code telling me that the Data is corrupt.
It tells me to turn off the system and try again.
I do so and it still happens.
I called Ninty this morning and they tried to help but the only thing they told me was not to redownload all of my old software at once... (This Unit replaces my old one)
So, I did that and it is fine for the smaller VC games.
But it still does it for the WiiU Retail Download games.
So, now, I'm downloading with the External Hard Drive unplugged directly to the WiiU. Then I have to turn off the System, plug in the External Hard Drive and transfer over everything.
Has anyone else had this problem?

Here is the Model # for my Hard Drive:
WDBACW0020HBK