Nintendo has warned owners of its new console to avoid bright lights shining near televisions while they play.
It follows reports that fairy lights were causing problems with the Wii's remote control sensor.
The technology giant said direct lights could cause interference in "exceptional conditions".
Writing on a users' blog, one owner said: "The last couple of days my Wii has been acting weird in not picking up the Wiimote on the side of the Christmas tree and I could never figure out what was wrong.
"Well tonight, I turned off the Christmas tree and it fixed my problem."
The Wii sold out within 24 hours of hitting UK stores earlier this month.
In a statement, Nintendo said the console wasn't affected by lights under normal conditions.
It added: "In exceptional conditions where the Wii sensor bar is sat near a direct light source there may be some minor interference - this does not mean that there is any fault with your Wii.
"For the best performance of your Wii, avoid bright light sources behind or near the TV, shining towards the Wii remote or reflecting off the TV screen."