Continuity mistake: Benson visits Stabler at his home to confronts him about the FBI detail he has ordered to protect her. They talk outside and then Benson is seen walking away. The next shot shows a side shot of Benson approaching him again in silence but mouthing words to him. (00:49:00)
Continuity mistake: Tony's hair length alternates between a short buzz cut and longer in different shots in the scene where Sil, Paulie and Chris visit him after his mother dies.
Revealing mistake: At the end it is not Helen against the filing cabinet - the face is different. Obviously a body double.
Character mistake: In the final episode, Carlos visits Doc in the psychiatric hospital for advice concerning his upcoming marriage to Holly. While talking, Carlos refers to Doc's deceased wife as "Linda", while throughout the series, it has been made very clear that her name was Deborah.
Continuity mistake: Emma falls off the roof and into a water butt when she is being chased by the villains, the police pull her out and she is soaking wet. A few seconds later she screams when the villain catches Nicola, and when they fall through the roof she is dry.