Continuity mistake: As Kasper Gutman talks to Spade about the Maltese Falcon, we see the bottle of liquor on the table go from half full to three quarters full in two shots without anyone going near it. (01:00:10)
Continuity mistake: Kasper Gutman drugs Spade and as they get up from the couch after speaking about the black bird we see a vase on table with roses in it. The roses have been rearranged and the items on top of the table have moved throughout the scene even though no one has gone near it. (01:03:20)
Continuity mistake: In his hotel room as they speak about the black bird, Kasper Gutman pours Spade a drink. A second glass appears on the table just before they sit down. (00:58:10)
Revealing mistake: In the final scene where Miss O'Shaughnessy is in the elevator with the detective, the door closes and the elevator starts to 'descend', indicated by dark glass going down, supposedly because the lighted elevator is passing beyond the view of the exterior door. But if you look, you can still see the silhouette of Miss O'Shaughnessy behind the glass, not moving. It is just a piece of wood or something being lowered behind the glass to simulate the elevator going down.
Continuity mistake: As Spade speaks to Brigid O'Shaughnessy in the first scene of the movie, just about everything on his desk moves between shots without being touched. (00:02:00)
Revealing mistake: In the last scene when O'Shaughnessy is being taken down in the elevator, one can tell that the elevator is not descending: rather something opaque is being lowered (like a window shade) to make appear as if it is descending. If you look closely through the translucent outer elevator door both the scissor-door pattern of the interior cab gate and the outline of O'Shaughnessy's torso remain stationary and don't descend.
Character mistake: When Spade leaves Brigid in her hotel room, he says he will buzz her buzzer long-short-long-short, so she will know it's him. When he does return, he only buzzes long-short.
Continuity mistake: Joel Cairo is knocked cold by Spade's upper cut and as he's unconscious Spade goes through his pockets. He takes his wallet out first and places it on the table behind him but by the time his hand reaches the table in the next shot the wallet becomes a watch. (00:25:40)
Visible crew/equipment: Before Spade walks into Kasper Gutman's hotel room there's one chair against the far wall. When he leaves the room there are two. (00:54:55)
Continuity mistake: Miles Archer walks in as Sam Spade speaks to Brigid O'Shaughnessy and he sits down. At the right side of his desk a coat hanger with a hat on it appears out of nowhere next to the window. (00:04:15)
Continuity mistake: Spade is a gracious host and offers Detectives Dundy and Polhaus a drink from a bottle that appears between shots on his night stand. (00:11:00)
Continuity mistake: Spade shows up at Brigid O'Shaughnessy's apartment as she's unpacking. The two slips that are draped over the open suitcase in the center of the room move as the scene progresses even though no one goes near them. (00:18:50)
Continuity mistake: As Kasper Gutman yammers on about the Maltese Falcon, we see Spade finish his drink. He never goes near the bottle but two shots later there's a small amount of liquid back in his glass. In the next shot it's empty again. (00:59:35)
Continuity mistake: The pillow on the hotel room couch moves between shots as Gutman pours Spade a drink. (00:58:10)
Continuity mistake: At the end of the movie Kasper Gutman's bowler is sitting flush on the table to left of him. No one goes near it but later in a close-up it rests at an angle on top of some other clothing. (01:19:20)
Continuity mistake: When Spade talks to his lawyer, Effie brings in Joel Cairo's calling card. Spade's packet of rolling papers are right next to his phone in some shots and not in others, even though he doesn't touch it. (00:23:10)
Continuity mistake: Miles Archer is shot and Sam Spade stands at the wood fence on top of the hill looking down at the body. When Miles is shot he holds onto the fencepost and there is no railing on the left or on the right, but when Spade stands there railing is on the left side. (00:08:20)
Continuity mistake: Spade walks into his office and Effie tells him that Kasper Gutman called and that Brigid O'Shaughnessy is in his private office. When he first walks in there's nothing by the water cooler on their left but several shots later he walks out to talk to Effie again and now there's a coat rack with several coats on it moved up next to the water cooler. (00:47:25)
Continuity mistake: Spade returns to his office the next day to find Iva Archer waiting for him. The lamp in the center of Effie's desk is removed between shots as he turns to look at her. (00:14:50)
Continuity mistake: Joel Cairo plays with his umbrella as he speaks to Spade about the possibility of him finding the Maltese Falcon. When he says, "I am prepared to pay, on behalf of the figure's rightful owner, the sum of $5,000 for its recovery," the handle of the umbrella changes positions between shots. (00:24:40)
