Continuity mistake: There's an electrical outlet on the wall below the window (aligned with the window shade's loop) in Sid's room near the Megadork poster, but when Sid throws Woody to the floor and raises the shade (before he scorches Woody's forehead with the magnifying glass), that outlet has vanished.
Continuity mistake: During Andy's daydream at the beginning of the film, Mr. Potato Head has an eye patch over his left eye. When the daydream cuts back to reality we see that Andy has removed Mr. Potato Head's left eye to symbolize the eye patch. But when Andy's mum comes in with the video camera, his left eye is suddenly back in. (00:01:15 - 00:05:25)
Factual error: When the fish tank has been cleaned by the newly installed laser fish cleaner, the machine states that the water temperature is '82°.' In Australia the Celsius scale is used; therefore, it should be about '28°.' Australia is 100% metric and has been since 1974! Nobody in Australia - nobody, anywhere, any time since 1974, uses imperial measures. There is absolutely no question of the dentist having an imperial thermometer or expressing himself in° Fahrenheit. It is actually illegal to import or sell any instrument using 'Imperial' scales. You couldn't buy a Fahrenheit thermometer if you tried. (01:14:30)
Continuity mistake: When the house first becomes detaches from its foundation and becomes airborne, Russell is nowhere to be seen, although every angle of the house is shown, including underneath, the front porch and the back porch. He knocks on the door and tells Carl he chased a "snipe" under the porch - but he cannot be seen after liftoff and prior to knocking. The same thing happens near the end, when Dug claims to have hidden under the porch.
Plot hole: During the scene where Merida gives her speech on "breaking tradition", her mother, as a bear, moves silently behind the majority of the crowd, so they don't see her. Fair enough. However, Merida and her father's clan are all looking in the same general direction (towards the crowd) while she's speaking - how does no one from Merida's clan see a bear moving at the back of the room?
Continuity mistake: After Dory reads the wall map while she's in the glass carafe, when Hank hides behind the rolling cabinet there's a long shot of the corridor with him at the far wall, then in the next shot from behind Hank a drinking fountain has suddenly appeared on the wall to the left, between two pictures.
Plot hole: Joy and Sadness are stuck outside of the control center. They are trying to figure out how to get back, and encounter maintenance workers who are discarding old memories. The maintenance workers show that they have the power to send memories back up to the control center to be played. Why couldn't they send the core memories that Joy had back up the same way? Better yet, why not use that method to send Joy and Sadness back up to the control center? The director of the film is even aware of the plot hole, and said "Yeah, well then we wouldn't have a third act," before explaining how the idea of recalling memories was added in later, "box[ing] [the screenwriters] in a corner a little bit."
Suggested correction: Even if they do send the core memories up to headquarters, they wouldn't be able to get joy and sadness through the tiny gap that the workers send the memories up. Joy has to be in headquarters for Riley to be happy.
This mistake is large enough that the director is aware of it. I think that more than qualifies it to be on this site.
Suggested correction: Joy is a control freak, she wants to return the memories herself. She doesn't even imagine that the workers can do such a thing.
Other mistake: When Elastigirl is chasing the high-speed train, as she is in the middle of making her second final jump to reach the train, if one were to look closely, the train actually drives right past her before she lands. (00:31:40)
Other mistake: When Skinner calls his lawyer he never dials the phone.
Continuity mistake: Near the end of the movie when the 'false' Buzz Light Year is running along the air conditioning ducts his 'New Utility Belt' disappears then reappears again. (01:01:55)
Continuity mistake: Tony Trihull appears when Finn McMissile begins chasing Professor Z. It also shows when Tony uses his magnet. When it is used, Finn's equipment are pulled by the magnet, which includes his bullets. Those bullets are black when all of them were going out. However, when they are pulled onto the magnet they are grey.
Continuity mistake: Before the race in Thomasville Cruz has the 20 number only on her right side but later she has the number also on her left.
Continuity mistake: When Sulley places the menu on the table he puts it face down (logo first), then when he lifts up the table, to quickly get Boo, the menu is face up. (00:26:05)
Factual error: As a trash compactor Wall-E does not function logically. When he fills his chest compartment with garbage and runs his internal compactor, the cube that exits his body is the same volume as the trash he puts in, despite that trash having been compacted. He does not add extra trash to fill the empty space after running the compactor - there are three scenes that show him filling up only once with loose garbage and then ejecting a densely compacted cube. (00:02:30)
Suggested correction: You haven't noticed the exact shape of his body. The back sticks out a tad. Garbage fills the space and the back pushes in to compress it.
Other mistake: After the first race, in the scene where Lightning is rushing out on the stage thinking he is the winner, loads of confetti is shot out when the King and Chick Hicks gets onto the stage. The confetti is then falling down, but not a single flake hits any of the cars. However, in the following shots, you can see plenty of it on the stage underneath the cars, even though they haven't moved.
Continuity mistake: When Lucius is putting aftershave on in front of the mirror, he hears the robot outside and runs to the window, leaving the bottle of aftershave on the desk with the lid off. He returns to open the drawer, and the lid is back on. (01:29:00)
Factual error: The size of the shadow of an object depends upon its distance from the light source, not the surface it falls upon. Lifting the cutout of the bird a few inches closer to the sun as they do would make absolutely no difference to the size of its shadow, yet it quadruples in size.
Continuity mistake: When they jump in the pool, they drop the guitar. When they jump out their guitar is no longer in the pool.
Continuity mistake: In the scene when Mike is at the school door lab. When he swipes the access card the door swings out. But when the campus police try to get in it is blocked from the inside, indicating the door opens inwards.
Suggested correction: If you look carefully, you will see, that those are actually two different doors, which even have hinges on different sides. There's some space between them in the entrance to the lab, it can be seen just before Mike enters.
Continuity mistake: Spot finds four other humanlike creatures and goes to them. Arlo is standing several feet in front of them. He begins to push some dirt by using his nose. A close-up then shows him using his nose to draw a circle around the five others but he is standing much too far away to be able to do this.