This YouTuber had a corrupted SD card on his Nintendo 3DS. You’ll never believe what happened next. ... Re-enter StreetPass Mii Plaza 6. Select SETTINGS and reactivate STREETPASS 7.

Some players are experiencing Super Smash Bros Ultimate save data corruption when using Piranha Plant, Duck Hunt, and Mii Swordfighter in two Games & More modes after the 2.0.0 update.