An email sent to affected players mentions that the bug is caused by performing a certain sequence of events during the Song of the Hero quest. After completing the sequence players are unable to continue using that save file forcing either a restart or a revert to an earlier save. Simply avoid this sequence during that quest (spoilers):
1. At the beginning of the quest, go to Lanayru Desert to retrieve the song of the Thunder Dragon.
2. In the Lanayru Mine, speak with Golo the Goron.
3. Complete the Thunder Dragon’s event, and receive his song.
4. Before heading to the forest or volcano regions, speak with Golo in the mine again.
5. At this point, the forest and volcano events will no longer occur, making it impossible to continue.
This issue WILL NOT OCCUR if the Fire and Water Dragon songs have already been collected before collecting the Thunder Dragon’s song. Talking to Golo in the Lanayru Caves will also NOT trigger this issue.
If the game has been saved after completing the sequence of events, it will no longer be possible to proceed through the game on that save file. The only options at that point are to either start the game over or to use an earlier save file to continue.
I wish I had a better answer, but I’m afraid there currently is no other fix available. I can assure, however, that we are documenting all feedback we receive on this issue. Thank you for your patience and support.
EGM’s TAKE: At least Nintendo acknowledged the bug exists. Now, they need to patch it before thousands of people choose the wrong sequence while playing the game during their holiday break.