Continuity mistake: As Marilyn walks into room 7-A of the City Morgue to identify her husband George she's carrying her pocketbook in her right hand. After she sees the body she faints and falls to the floor but we never hear the pocketbook hit the floor because it has been neatly placed next to her before she fell. (00:42:05)
Continuity mistake: At the Rainbow Cabins, Mrs. Kettering hands Polly Cutler a bouquet of roses and the pink bow is on the left. In the next shot the bow is rotated 45 degrees to the right and is now facing Mrs. Kettering. (00:44:10)
Continuity mistake: When George Loomis comes back to the cabins, after the lover tried to kill him at the falls, he wears the lovers shoes. But after he walks on the grass, just before the end of the shot, the top of the shoes is not white anymore as if he was wearing his own shoes. (00:45:00)
Continuity mistake: At the Rainbow Cabins, Polly Cutler speaks to the Kettering's and holds a bouquet throughout the scene, and it keeps changing positions between shots. (00:45:05)
Continuity mistake: Mr. Qua is watering the flowers and as Polly Cutler speaks to the Kettering's we see the front of the car and there's no water on the gravel by the tire. After they get into the car and drive away in the next shot, there's a lot of water on the gravel. (00:45:15)
Continuity mistake: Polly decides to take a nap in cabin B and the ash tray on the night table moves to the edge during the scene without her going near it. (00:46:45)
Continuity mistake: Sunlight is coming into this room from all directions. At first it is coming from the right of the screen. Then when Denis O'Dea goes into the kitchen (screen left), sunlight is coming from the other direction. (00:48:40)
Continuity mistake: Ray Cutler decides to leave the Rainbow Cabins and says to Polly, "Give me a hand with this stuff, will ya, Honey". As he says this he picks up a suitcase which has nothing on top of it, but when we saw it earlier in the scene there were clothes on top of it. (00:49:35)
Continuity mistake: Ray Cutler decides they should leave the Rainbow Cabins and picks up one of two stacks of books on a table to the right of the front door as he talks to Polly. No one goes near this spot but earlier in the scene there was only one stack of books along with a pocketbook (which is now on the floor) on the table. (00:49:45)
Continuity mistake: George Loomis chases Polly at the Cave Of The Winds and she almost gets killed braking apart the wooden rail as she runs into it. The part of the railing hanging on the left changes position between shots. (00:54:40)
Continuity mistake: Marilyn sleeps in her hospital bed as the song "Kiss" plays from the bell tower. At first she's sleeping on her back then in the next shot she's on her side. (00:57:15)
Continuity mistake: Marilyn walks up to the ticket booth and gets a refund for one of the tickets to Chicago that she bought earlier in the movie. Looking at her luggage we see no marks on it at all. She picks it up the same way she puts it down, but in the next shot a large black mark appears on the front of it. (01:01:15)
Continuity mistake: In the bell tower the shadow is at about 45 degrees, but when Marilyn walks there the sun is overhead. (01:03:10 - 01:05:40)
Continuity mistake: George Loomis strangles Marilyn who falls to the floor of in the bell tower holding a yellow scarf near her face. In the next shot it's held away from her body. (01:06:25)
Continuity mistake: Before George Loomis strangles Marilyn in the bell tower she knocks everything out of her pocketbook looking for a dime to make a call on the second floor pay phone. We see the items on the floor as George walks past on his way to kill her, but later when he returns and picks up her lipstick everything has been moved. (01:07:25)
Continuity mistake: After fishing on the Niagara river with the Cutler's, Mr. Kettering pulls his boat up to a dock that is in the shade. In the next shot the dock is in the sunlight. (01:11:30)
Continuity mistake: Two Canadian motorcycle police drive up and speak to the boat keeper about George Loomis, and a prominent tire mark is on the side of the road in front of the black car. The next time we see this spot as Ray and Mr. Kettering run to the boat it's not there. (01:12:20 - 01:17:10)
Continuity mistake: When the Canadian motorcycle police drive up and speak to the boat keeper about George Loomis they're all in direct sunlight with no trees anywhere near them. When they leave several shots later it must be an entirely different time of day because shade from the trees across the street covers the entire set. (01:12:25)
Continuity mistake: When the Canadian motorcycle police drive up and speak to the boat keeper about George Loomis, one is wearing a white shirt and the other a blue shirt. In the next close-up shot they're both wearing blue shirts. (01:12:25)
Continuity mistake: As the Canadian motorcycle police drive away George Loomis hides across the street behind a boat and some items that look like they belong in a tag sale. In the next shot as he walks away all of the items on the right of the boat have been rearranged. (01:13:10)
