Continuity mistake: Not only does Andy not have the bagel when she enters the subway stairs, but she is wearing her gloves/mittens when she does - when the bagel reappears, they are gone.
Continuity mistake: In the scene right after Andy finds out about Miranda's divorce proceedings, she goes back to her hotel room to get ready for her date with Christian. When she looks at her reflection in the mirror as she's applying mascara, her hair is a little tousled and tucked behind her ears. In the very next shot, her hair is untucked and perfectly in place.
Continuity mistake: When Andy sees Miranda on the street at the end of the movie, Miranda gets into a Mercedes then tells the driver to go. When the car takes off, Miranda is in the car but as the Mercedes drives away, Miranda is no longer in the car.
Continuity mistake: When Andy first meets Christian at the party, her hair changes throughout the scene. First one side is in front of her ear, then it's tucked behind it, then it's in front again.
Continuity mistake: At the beginning of the scene, when Miranda and Andy discuss the Paris trip at Priestly's house, she calls Andy and asks if she has the book. In between the shots of Andy and Miranda, she hands her the book twice.
Continuity mistake: When Andy answers the office phone for the first time, the blue post-it notes that had been right next to the monitor's base, have moved a couple of inches, even though no one touched them.
Continuity mistake: At the James Holt party when Andy collects the dress sketches, the man behind James and Andy with the dark hair (dreads?) pulled back into a bun changes position with each shot.
Continuity mistake: When Emily is saying "This is what you are doing" and closes her hand, her pinky and her ring finger are up. But in the next shot, shot from the back of her, her pinky and ring finger are closed. In the next shot, in front of her, her whole arm is down. There is no way she could have put down her hand that fast.
Continuity mistake: When Andy arrives at the office, she's wearing black hose. She then goes to James' Holt's office and isn't wearing any or is wearing nude hose. Later, she's wearing black hose again.
Visible crew/equipment: When Andy and Nigel are discussing him getting a new job, he walks over to the big windows. When we first see him at the windows, it is a very quick shot, but you can see a crew member in the background.
Factual error: When discussing the couture shows/designers that Andy will be seeing in Paris, Doug mentions "Nicolas Ghesquiere", the head designer for Balenciaga, a house that doesn't currently show Haute Couture.
Plot hole: Miranda forces Andy to tell Emily that she's been dropped from the Paris fashion trip. However, Emily is hit by the car before Andy delivers the bad news. Andy finally tells Emily at the hospital but there was no need to give the real reason she was replaced because Emily could not have gone to Paris with a broken leg. Even at the end of the movie, which is after Paris, Emily is hobbling around with a cast and on crutches.
Continuity mistake: In the scene where Andy is visiting Emily in the hospital, the arrangement of food items on Emily's tray changes between shots.
Continuity mistake: When Andie is talking to Christian in the French restaurant, she is wearing dark eyeshadow. But after dinner, when she kisses him outside his hotel, her eyeshadow is just a light beige. (01:26:55 - 01:28:20)
Other mistake: When Andy is talking to Christian outside the fashion event at night, he says, "If it weren't for the stupid boyfriend I would have to whisk you away right here and now," except Andy has never mentioned that she had a boyfriend. (01:04:58)
Suggested correction: It's quite likely that Christian knows this without Andy telling him. He and Andy know some of the same people who are associated with "Runway" (later on, he reveals the plan for Miranda to be fired). He probably has "connections" and keeps up with gossip.
Other mistake: Andie lives at Broome and Orchard, in the heart of the Lower East Side. Average rent for a one-bedroom apartment (which they have) was $2217 at that time, and Nate and Andie both make barely minimum wage. That rent would have taken their *entire* combined salary in 2006. They didn't depend on help from their parents, since Andie's surprised when help arrives. And the apartment wasn't rent-controlled; Andie and Nate aren't from New York.
Suggested correction: This submission is making assumptions. When is it stated that both Andie and Nate are earning "barely minimum wage"? They may not be upper-middle-class, but their two incomes are never described as "barely minimum." In one scene, the friends raise their drinks in a toast to "jobs that pay the rent." Also, Andie might be surprised to receive money from her father, but we know nothing about Nate's family.