So, are you getting error code 150-1093 from your Wii U, with games freezing at load? While the issue sounds like a real pain, the fix is actually much simpler than you might think.
Error code 150-1093 comes from attempting to load a game from an external hard drive that is not powered. Nintendo has already said that external USB hard drives must be powered by using a two port USB y-cable or an external power supply that plugs directly into the hard drive.
The easy fix is to just to get a powered hard drive and use it as your Wii U hard drive of choice. In the meantime, the simple solution is just to transfer the game’s data to your system flash memory (provided that you have enough space, of course) while you are playing the game. Long term, a powered USB hard drive is simply the best way to go.