Visible crew/equipment: After the ship's captain delivers the Falcon to Sam Spade's office, he collapses on the leather sofa in the foreground. Just after Spade's secretary says, "Is he ...?", the shadow of someone's head passes over the sofa.
Continuity mistake: At Spade's apartment, Brigid O'Shaughnessy tells Joel Cairo, "I haven't got the falcon, I'll have it in another week at most, though". The lamp on the table of the right of the screen changes position throughout the scene without anyone going near it. At first it's pointing downward then later it's pointing sideways at the three of them. (00:35:35)
Audio problem: When Effie says on the phone to Archer's widow "no, not yet" her lips do not move.
Continuity mistake: When Joel Cairo returns to his hotel after being interrogated by the police he asks for the key to Room 603 - but earlier he has told Spade that he lived at Room 635. (00:44:30)
Continuity mistake: The police visit Spade's apartment after Miles Archer murder and we see a nice tie rack with several ties hanging off of it behind the lamp near his night stand. Earlier in the movie we saw this spot when he got the call about the murder and the tie rack was not there. (00:10:40)
Continuity mistake: Brigid O'Shaughnessy goes into the kitchen to make some coffee and hands Kasper Gutman the $10,000. He shows Spade nine bills and claims that she pocketed one of the thousand dollar bills. Spade gets Gutman to admit that he, "palmed it" but if you look closely the money is never out of our sight and he never palmed anything. (01:23:45)