Goofs

When Caul is in Stett's office alone, he walks over to the desk and picks up one of Stett's wife's cookies. He smells it and puts it back in the dish and then looks through the telescope. When Stett returns, he hands Caul the money and takes the tapes. When the film cuts to a shot of Caul thinking about the arrangement, the cookie reappears. Caul puts this cookie back in the dish, too.

Throughout the film, Harry listens to the recording of Mark telling Ann,"He'd kill us if he got the chance," which creates empathy in Harry and motivates his actions in the story. However, at the end of the film, after the Director has been killed, the recording plays again, and a new emphasis completely changes the meaning of the playback: "He'd kill US if he had the chance," indicating that Mark and Ann are justifying their plan to kill the Director, not the other way around. There is no explanation for the change in the recording.

When Harry is talking with Bernie in the workshop during the party, the chain on the device hanging from the ceiling is swaying vigorously, but when the scene cuts mid-sentence, the chain is now perfectly still.

When Harry Caul is in the elevator, you see the woman come in and three buttons are pushed. After stopping on a floor, a cut back to the shot of the woman and only one button remains lit whereas two should still be lit.

Harry Caul is the top surveillance expert with custom equipment that he designed himself and is extremely paranoid but illogically allows the other surveillance experts to enter his lab and examine his equipment.

Harry Caul is a Catholic and he takes exception to others who use the Lord's name in vain while in his presence. However, he lies repeatedly about not having a home phone. When he confesses his sins to a priest, he admits that he himself has taken the Lord's name in vain several times and reveals that he may have contributed to, or even caused, the death of one or more people. However, he says nothing about having lied about having a home phone number.