I am not sure how reliable is this source, but here it is:
My son was really excited to get this game last Friday. Unfortunately,
his enjoyment has been tempered by the extreme bugginess of the
release. Since he made it to the 6th year, the game has crashed
constantly. We finally called customer service this morning and were
informed that it has been recalled. We will be sent a new disk in the
There are other sites that talk about LEGO Harry Potter 5-7 recall, so probably it is better that you contact the customer service too, or your game reseller.
A possible fix it suggested here at Guide4Games.
Adjust sound settings to "Stereo" or "Mono" from "Surround":
- In Wii Channel menu -> Select Wii Options -> Press A Button
- Go to Wii Settings -> Press A Button
- In Wii Settings menu -> Go to Sound -> Press A Buttton
- Select "Stereo" or "Mono" -> Press A Button to confirm
- Re-start LEGO Harry Potter Years 5-7