Double Indemnity (1944)

Continuity mistake: Throughout the movie, Fred MacMurray wears his wedding band, even though it's mentioned several times that he is single.

Continuity mistake: When McMurray enters his office at the start of the film, he places his hand on the table and sits down. The position of the hand is different between shots.

Sacha

Continuity mistake: When Fred MacMurray and Barbara Stanwyck are talking to each other over the grocery shelf, she has to stand on tip-toes to see him, and even then the boxes on the shelf cover most of her face. But in the tight shots the boxes are down by her shoulders. She even walks off-screen without coming down off her tip-toes.

Continuity mistake: Neff's shirt collar is unbuttoned as he and Keyes talk at his apartment. When their conversation carries into the hallway, his collar is buttoned up. As Neff and Dietrichson go back into Neff's apartment, it's unbuttoned again.

Continuity mistake: In the scene in Norton's office where Keyes says "next time I'll rent a tuxedo", Neff goes out to the outer office first and when he gets there, we see him bend down to a table. But in the next shot, Keyes comes out after him and Neff is not bent down.