Important: Please do not power off your Wii U Console during the System Update.
What to do:
1. From the Wii U Menu, select "System Settings".
The current menu version will be displayed in the top right corner.
2. Using the Left Stick, scroll to the "System Update" icon and press the A Button.
3. Tap "Update" to connect to the Internet and begin the update process.
If your problem is still not resolved, please contact Nintendo Consumer Support.