It is because it's USB3, or because it's a portable harddisk?

I started to found myself spending more time to test various configuration of harddisk, disk partition, and other setup with WiiFlow on WiiU, then actually playing games on it.  Ironic.

By the way, a side note: I just realized that my Dell XPS has serious problem recognizing or maintaining connection with USB2 harddisks, but seems to have no problem with USB3 harddisk what so ever.  Very strange.

So I tried using various USB2 portable 2.5 inch harddisk, including a 320GB USB2 harddisk, a 1Tb USB3 hard disk, and all of them failed.  On the other hand, the USB2 3.5 inch harddisk dock that I have works fine with WiiFlow.  So I guess I'll just have to stick with the non-portable harddisk then.

To be fair, the was ONE time that WiiFlow recognized and showed up the right game list, but obviously it's not consistent enough for me to consider using it daily.