Continuity mistake: On Claire's business card it says she works at Operation Reach Out, but the sign on the building says Operation Outreach.
Factual error: The address on Claire's business card reads 514 West 43rd St. When Frank gets there, the street sign is for 3rd St./900 East block. The sign on the building reads "9th Street Temporary Shelter". Along with these discrepancies, taking into consideration that 3rd St. may be the cross street, WEST 43rd would not cross 3rd St. EAST, as they are on opposites sides of Manhattan. Even if the '4' on the sign for 43rd St. were somehow obliterated, 514 still would not be on the 900 East block. (00:53:10 - 00:54:15)
Continuity mistake: When Elliot shoots at Frank, he hits a wreath hanging on the wall, and it bursts into flames and falls to the floor. Later when it's laying on the floor however, it has what looks like ashes on the floor around it, but the wreath itself is still perfectly green and not burned at all.
Continuity mistake: In the scene where Bill's old boss comes back to see him notice when Bill shoots him and takes the drink. All of the drink comes out of his chest because of the bullet holes. Well notice his shirt is all wet, then in the next scene when he takes off his hat his chest is all dry.
Factual error: The Ghost of Christmas Past takes Frank to the year 1969, where he watches his younger self giving Claire a set of twelve Ginsu knives on Christmas Eve. Young Frank even remarks that the Ginsu knives are sharp enough to cut through a tin can as easily as a tomato. Problem is, Ginsu knives didn't arrive on the market until 1978, which is when the tin-can-cutting demonstration was first used.
Visible crew/equipment: When the Ghost of Christmas Present settles to the ground after floating down the stairs at Frank's brother's house, you get a brief glimpse of the wires attached to her back.
Character mistake: When Frank opens the present in his office and finds the picture frame from his brother inside, he reads what is supposedly written on the frame out loud: "To Frank, the best brother a guy ever had. Merry Christmas." However, instead of Merry Christmas, it says Love, James.
Continuity mistake: In the meeting when they show the advertisement for IBC's Scrooge, the Mary Lou Retton scene used in the commercial is the exact same shot that takes place before the live production of Scrooge days later. It shows Alfre Woodard and her son watching Mary Lou as she flips, which cannot be possible because it took place in the future. (00:04:00 - 01:12:00)
Other mistake: When Frank and the Ghost of Christmas Past are at the office Party where the younger Frank is still working, as they stand by the entrance door two women leaving move in closer to try and avoid bumping them - despite the fact that the Ghost said earlier they couldn't be seen or affect what's going on.
Deliberate mistake: In the end scene at the TV set, Scrooge tosses a coin out the window, and the camera follows the coin as it falls in slow motion. The people in the control room also watch this on their monitors. Problem is, this is a live broadcast and filming/watching something live in slow motion is impossible.