Every time wiiu lost connection with hard disk the hard disk will have to be reformatted to be used. That means loss of save, damage to hard disk, and have to re-download. It seems like system problem and is there a way resolve this
Nothing to do with power supply (I bought a disk case), it is just wiiu cannot read the disk after re-connectionPurchase a Y cable. Perhaps there is not enough power to power up the HDD.
Are you trying to use it for WiiU storage or for USB loading (or something of that sort) in the vWii?
If the latter, try not plugging the usb cord into the WiiU until you've already entered Wii mode and see if that helps.