Continuity mistake: At 1972 Canyon Drive as he talks to Evelyn Mulwray, the curtain above Jake's head extends almost halfway to the center of the rod. Earlier when we first saw it, it was pushed all the way to the left side. (01:48:40 - 01:52:20)
Continuity mistake: At 1972 Canyon Drive, Jake sits down and says to Evelyn Mulwray, "Do you know any good criminal lawyers?". If you look closely the dress on the chair to his left has been rearranged between shots. (01:48:45)
Continuity mistake: After Jake slaps Evelyn Mulwray, the vase on the table on the right of the sofa disappears between shots. (01:50:35)
Continuity mistake: Throughout the scene at 1972 Canyon Drive, the handle on the hat box to the left of the sofa changes in relation to the hat sitting on top of it. (01:50:55)
Continuity mistake: At 1972 Canyon Drive, Jake speaks to Evelyn Mulwray and there's a dress lying on the open suitcase behind her as she sits on the couch. In previous shots, it's not in the suitcase, and no one went near it. (01:52:20)
Continuity mistake: At 1972 Canyon Drive before Jake meets Katherine Cross, the dried flowers in the vase behind the sofa have been rearranged since we saw them at the beginning of the scene. (01:53:20)
Continuity mistake: Jake takes Lieutenant Escobar to Curley's house and as they drive up, he takes his right hand off of the backseat of the car. In the next shot both of his arms are leaning over the backseat. (01:56:00)
Continuity mistake: Jake takes Lieutenant Escobar to Curley's house, and the flower pot on the ledge and the shades in the window move between shots after he walks up to it. (01:56:55)
Continuity mistake: John Huston sees Katherine Cross and says to her, "I'm your grandfather," and we see a black car passing by them on the road. In the next shot, it's gone. (02:05:15)
Revealing mistake: When Gittes visits the orange grove and crashes into the tree, you can see that a steel plate has been placed around the tree to protect it.
Continuity mistake: Throughout the movie, keep an eye on Jack Nicholson's tan. He goes from a toasty brown to washed out to toasty brown several times, in the same lighting sometimes he appears pale and sometimes he's tan.
Continuity mistake: When Jack's trying to outrun the guys shooting at him, they shoot his tire, sending the trim ring flying. However, when the car nails the tree, the tire looks completely undamaged and the trim ring is back on.
Continuity mistake: Gittes finds Mrs. Mulray's big house being shut down, finds the eyeglasses in the saltwater pond and races to the small house where Mrs. Mulray's daughter had been staying. All their luggage was there at the small house because they were leaving there to go directly to the train station to make their escape to mexico. The Mulray entourage (daughter and servant) hurriedly leaves the smaller house without their luggage since Gittes had called the detectives. After Gittes takes the detectives on a deceptive trip to Curly's and eludes the detectives by Curly driving away with him, the next scene has Curly and Jake putting the last of Mrs. Mulray's entourage's luggage into Curly's truck in front of the Mrs. Mulray's large home, not the smaller house where the daughter had been staying and where they had all their luggage together to go straight to the train to escape to Mexico. The sequence should have had Gittes retrieving luggage from the smaller house.
Revealing mistake: When Jack Nicholson slaps Faye Dunaway, the first time we can see he doesn't actually hit her. We see a shot of him raising his hand, then a shot of her jerking her head like she was slapped, but his hand doesn't touch her, or even go anywhere near her.
