Some users have been reporting problems when trying to run downloaded Wii titles from an external USB hard drive.
Now that Nintendo is offering players the opportunity to download Wii titles via the Wii U eShop, it seems that there are some issues that need to be fixed. A small number of users have reported bugs like black screens and game crashing when running the likes of Super Mario Galaxy 2 off an external storage device.
When loading the game from the Wii U's internal storage, however, it appears to work correctly.
Nintendo have yet to comment on the issue at time of writing.
Have you encountered issues with running Wii titles on Wii U via a USB drive?