Continuity mistake: When the girl gives Litwak her phone to show him there is a replacement part on eBay, her phones shows that it is connected to WiFi. Litwak doesn't set up his router until later that evening, he has only plugged it in. (00:09:41)
Suggested correction: It's possible she's either connected to wifi at another nearby business, using a public wifi signal, or using a friend's phone as a hotspot.
Other mistake: Vanellope steals a car from the Slaughter Race game and speeds off. Shank, the main character of the game, commandeers another car and chases Vanellope. When Shank's car is seen in Vanellope's rear-view mirror, the image is not reversed. Shank appears to be driving from the passenger seat.
Suggested correction: We see the mirror and it in fact is a mirror image of Shank driving.
Factual error: Near the beginning of the film there is a warning sign that the "Tron" game has a virus. How does an arcade game get a virus?
Suggested correction: I don't believe it was actually a virus in the game. It was more of a bug in the coding that arose, probably in just that particular cabinet after wear and tear. However, the characters in the arcades would not really have a full understanding of a virus and would conceivably use the terms of virus, bug, and possibly even glitch interchangeably. I don't think it was an actual virus or a mistake in the movie, but just the miss-information that the characters were going off. Especially seeing as how we see the physical/cyber manifestation of a virus later in the film.
Respectfully, that's just speculation. What you "believe" to be the case doesn't make it so.
