I’ve got MK8 and it runs fine on my Wii u.
Was it the update when the extra tracks and cars were added, the paid for dlc content?
What I can’t get my head around is how they can fix software by sending the disc back. Surely, either it loads right or it doesn’t, or is that too simple.
I presume all your other games work OK as I wondered if the memory on the Wii u, where the updates are stored, is corrupt?
What size disc do you have, 8gb or 32gb? Is it nearly full and preventing the updates storing?
I’m not an IT expert, just a fellow Wii u owner so making random suggestions but I feel your pain as MK8 is brilliant. The number of Cadbury fudges I have won from the kids* in Grand Prix challenges is legendary in our house.
*tempers that somewhat as my 9yo lad is very quickly getting the knack and I fear it’s going to start costing me!