Patzer

The size of Miles Finch's black notebook changes. The book held by Eugene later is much wider than when Miles' book is seen the first time.

When Buddy and Michael take cover behind the snow bank during the snowball fight, rips in Buddy's tights can be seen in his inner thigh area during one shot, but not in the others.

In Central Park when Santa is trying to fix his sleigh, the trap door is open, but when Michael comes to help Santa, Santa asks Michael to open the trap door for him.

In Central Park, while trying to fix Santa's sleigh, Buddy is seen through the trap door. But in the long shot, as the sleigh rises off the ground a few feet, Buddy has disappeared. This happens several times.

The position of the blue book in the executive's hand behind Buddy when he first meets and sings for his father changes repeatedly between shots.

Blood samples for paternity testing are sent to specialized labs to perform DNA analysis. The testing cannot be performed in a doctor's office with results being obtained in only a few minutes as depicted.

Paul Simon and Art Garfunkel's concert in Central Park was in 1981, not 1985 as the news anchor says when talking about the "Central Park Rangers."

Almost everything about Walter Hobbs' publishing company is wrong. Companies have a long queue of books that they work on, so they wouldn't waste time working on brainstorming a single book for weeks at a time. They also get their book manuscripts from authors who reach out to them, rather than the other way around. It's unclear what Walter even does at work if there isn't a bunch of books to be working on in the queue.

The trucks on the skateboard that Santa gives Michael are facing the same way. It would be impossible to turn like that; a skateboard is put together with the trucks facing opposite each other.

Roughly 36 hours pass from the time Walter orders the incomplete book shipped to Fulton's niece getting the book and complaining about the missing pages, add to that the poor sales record the book was accumulating (a minus 8). In real life, it would've taken at least a week, two at best, for the book to be fully published, hit shelves and be purchased by enough people before poor sales records would be known.

Papa Elf tells Buddy about his birth and gives him a photo of his parents (which appears in their yearbook later on). It can be assumed he got the story from Santa, but it's unknown how (or why) Papa Elf got the picture.

He also would have gotten the picture from Santa. Santa is magical and knows who's sleeping or awake, who is good or bad, etc. It would have been no problem for a magical elf to get a picture.

Buddy is a normal human being brought up by Santa, Papa Elf and elves. However, during the snowball fight with the bullies, Buddy exhibits super-powers of super-fast snowball making, and super-fast snowball throwing.

This is because he has lived in the magical environment of Santa's workshop and acquired these abilities by association with the elves. In fact, when Buddy tells Santa he is not an elf, Santa says "You're more of an elf than anyone I met."

When Michael is reading from Santa's list, he recites the names as they are listed. Suddenly, when given a name to "look up," he says "D" and flips pages looking for "D" as if the book is in alphabetical order. However, the names he already read are in no particular order.

When Buddy is in the mail room and puts the side of his face on the vacuum mail tube, there is no ring left on his face from the sucking once he pulls it away.

The police precinct interior has green-lit "EXIT" signs, which are found in states like California and Washington, not in New York City, whose "EXIT" signs are lit red.

When Michael and Buddy are jumping in the elevator, the elevator bounces before they actually land on it.

When Buddy and Leon are talking they are both "walking." Leon is making an impression in the snow as he "slides" along, but Buddy's footprints are making no impression.

Gimbels went out of business in 1987.

When Buddy is in New York, there are crosswalk signals that read walk/don't walk. In New York, these signals were replaced by the white pedestrian and the red hand in 1999.

The raccoon that attacked Buddy makes the sound of a monkey.

When Jovie is singing in the shower, after Buddy joins in she stops singing but her voice can still be heard.

When Buddy chases Michael down the street from the school, a crew member in a yellow hat can be seen trying to duck back behind a doorway of a house on the street.

When Jovie is first seen singing in the shower, her body stocking is visible.

When Buddy is in the elf classroom, the platform on which his desk is sitting to aid in forced perspective is visible at the bottom of the screen.

Peter Dinklidge's stunt double is visible when Miles Finch kicks Buddy after running across the table.

When Buddy discovers Santa in Central Park, a tether holding the lead reindeer in place is plainly visible, running from his harness off the left-hand side of the screen.

The film's exterior of Gimbels department is not a digitally altered view of the Macy's flagship store on 34th Street in Herald Square, Manhattan but is actually 295 Fifth Avenue and 30th Street, also known as the Textile Building.

Jovie agrees to a date with Buddy, telling him that she is free on Thursday. She does not specify a time or let Buddy know where she lives, and Buddy does not have her contact information (nor she his).

When Buddy climbs out of Santa's bag as a baby, the elves surmise that he must have gotten into Santa's bag at the orphanage and that his name must be Buddy because of the diaper company name. Santa would know all children and their names; therefore, he would have known the child's name and situation.

At the clinic. When the doctor gives Buddy a shot and he starts screaming. Walter is shown covering his face and laughing. Breaking character.

At the moment just after Santa and Buddy fly over the crowd of revelers outside Central Park, several of the actors miss their mark at where to look. James Caan and the extra in the right-foreground appear to be looking correctly at where the sleigh was at in the very previous shot, while the other actors are either looking straight up near 90 degrees and Mary Steenburgen doesn't appear to know where to look.

While giving Buddy advice for his trip to New York, Santa adds that there are about 30 Ray's Pizzas that all claim to be the original, but the real original location is on 11th Street. However, Santa is incorrect. He is referring to Famous Ray's Pizza, which at the time, was located at Sixth Avenue and 11th Street, and operated between the 1970s and 2011. In actuality, the first Ray's Pizza, which operated between 1959 and 2011, was located at 27 Prince Street on the northern edge of Little Italy, Manhattan at the time.

When Jovie suggests Buddy was trying to see her naked in the shower, Buddy truthfully says he did not know she was naked. However, earlier in the film, Buddy was shown in the shower himself. Clearly he is familiar with the concept and should have known Jovie was naked.