After Rick hide the free-transits under the stack of papers on Sam's piano, he walks away and waits while Sam finishes playing. When he comes back to talk to Sam, the stack of papers is on the other side of the piano.
When Signor Ugarte is explaining to Rick about the letters of transit, he says they are signed by Général De Gaulle, and therefore cannot be questioned. To be valid, they would have to be signed by Maréchal Pétain, and not Général De Gaulle.
There are multiple instances throughout the film where the action of Sam's hands on the piano bears no resemblance to the piano part heard. Especially notable is the first time Sam sings "As Time Goes By" for Ilsa; a rapid treble run is executed that would have necessitated the movement of his right forearm. None is seen.
When the bartender spins Rick around on his chair and kisses him on both cheeks, saying, "Boss, you've done a beautiful thing," Rick smacks him on the back and replies, "Get away from me, you crazy Russian." We hear the sound of the smack quite a while after Rick hits the bartender.
When Rick and Ilsa are listening to the sound of German guns out the window in Paris, Rick comments that they are from the "New German 77s". Actually, the German Army used a 77 mm. field gun in World War I, not World War II. The script writers, (or perhaps Rick himself) may have been thinking of this older weapon.
Ferrari's "blue parrot" is a different species. It is hard to tell in black and white, but based on the face patch, size and gray scale of the colors, the parrot is a scarlet macaw (red and yellow with blue wing tips) or Ara Macao; and not a blue macaw (hyacinth or blue and gold).
During Rick and Ilsa's night together in Paris they hear artillery firing; and Rick says that "it's German's new 77." The German's didn't use the 77 in World War II. They did use a 77mm gun in World War I; but in World War II the 88mm gun was the new gun.
Right before showing Rick the letters of transit, Ugarte begins lighting a new cigarette with his previous cigarette, but gives up doing so and puts the unlit cigarette on the ashtray in front of him, where it rests partially on the table. Moments later there are two cigarettes in the ashtray, none of which are resting on the table. Moments later, as Ugarte leaves the table, the cigarettes have disappeared from the ashtray.
While Captain Renault is chatting with Rick outside the Café Américain, the medal to the left on Renault's tunic clearly extends below the pocket flap. In the next scene the medal is significantly smaller and does not extend below the pocket flap.
An extra (elderly man with white goatee and hat) is shown being herded into the police station along with other "usual suspects" and shortly thereafter is seen along the street peering upward at the German plane coming in for landing.
When Major Strasser talks with Rick about Laszlo, he leans his elbows on the table and crosses his fingers. In the next shot he is raising his right hand to join his left. And after, between cuts, he appears with both arms leaning on the table.
When Major Strasser steps out of the airplane upon arrival in Casablanca, another officer is also stepping out behind him. In the next frame, the Major has shifted backwards and the other officer steps out of the plane once again - and 3 soldiers saluting with guns (and a cart) have suddenly appeared along the trailing edge of the plane's port wing.
As Rick steps out of his office to hear the Germans sing, Major Strasser is seen sitting at the end of the piano. Moments later, Strasser has shifted to the right, and the German officer, Heinz, and a large vase has appeared. A few moments later, as Yvonne appears in a shot, Heinz has disappeared again and Strasser shifted back. Also, the table that Yvonne is sitting at was occupied by another couple when Rick stepped out of his office. Later, as the La Marseille is being sung, Heinz reappears at the German table.
As we see the Germans start singing, the bar behind them is empty. Moments later as Rick steps out of his office, a French officer has appeared at the end of the bar. Moments later the camera pans from the singing Germans to the bar where two old men have suddenly appeared and the French officer has shifted further down the bar.
When Rick is listening to Annina explain the situation in Bulgaria with his back to the camera, we see him take a drink of brandy. The shot switches before he put his glass down. But in the new shot with the camera facing him, Rick only has a cigarette in his hand and the brandy glass isn't visible.
Ilsa sends the waiter to call Sam. Sam pushes the piano to Ilsa's table. When Rick comes to reprimand Sam for singing "As Time Goes By," he is standing next the piano, which Sam has pushed away from the table. In the next long shot, Rick is a little ways from Ilsa's table, which has changed places.
When Laszlo enters Rick's for the first time, he puts his hat on a chair next to the one he sits in. Later, before Capt. Renault sits on the same chair, Laszlo picks up the hat and puts it on the floor. When Laszlo leaves, he does not pick up his hat. But when he leaves Rick's, he is holding his hat.
When Rick places the letters of transit under Sam's pile of sheet music on the piano, the sheet music is on the right side (from the back) and Sam's ashtray and drink are on the left. Later the drink and ashtray are on the right and the sheet music is on the left.
An extra (elderly woman in a flowered dress and dark hat) is shown being herded into the police station along with other "usual suspects" but moments later is shown herded off a police van and in the next shot she is again herded into the police station. Furthermore, shortly thereafter she is seen along the street peering upward at the German plane coming in for landing.
When discussing with Renault outside the café, when Rick sits down there is a piece of paper on the table along with a white, square dish, and an ashtray. A little later, the paper and the white dish have disappeared. Instead, a bottle has appeared and the ashtray has shifted position. Moments later, the dish and the paper reappear only to disappear again.
During Renault's first visit to Rick's office, Renault sits in a sofa in Rick's office. To his left is a table. When he gets up from the sofa, a small figure of a woman has suddenly appeared clearly visible on the table.
Upon arrival at Major Strasser's table during Strasser's first visit to Rick's, Captain Renault puts his cap on the table next to a sign showing that the table is reserved. Shortly thereafter, during Ugarte's arrest, the cap has disappeared as has the sign.
In the initial scene at Bella Aurore where Rick pours champagne, Rick puts down the bottle on Sam's piano so that the label faces the camera, but a few shots later the bottle has turned so it is now turned sideways as seen from the camera.
In the La Belle Aurore scene, when Rick and Ilsa hear the German loudspeaker outside, Rick picks up the champagne bottle and walks toward the window leaving his glass and the bottle of champagne on a table. As he puts the bottle on the table, it ends up with the label non-visible facing away from the camera. Upon returning to the table five shots later, the bottle has turned 180 degrees so that the label faces the camera - and a champagne cooler with another bottle has disappeared.
Before the beginning of the Paris flashback, Rick is sitting with his back to the door. After the flashback, he has shifted to the other chair, his original chair having been knocked over - and he is now using the other glass on the table.
When Rick is asked by Renault whether or not Rick has the letters of transit, Rick is drinking from an almost full bottle that Carl moments before has put on the table. A few moments later, when Rick pours Renault a drink, the bottle is less than half full. After Yvonne passes by the table, the bottle is suddenly more than half full.
Right before Ilsa pulls a gun on Rick, he is seen lighting a cigarette. In the next few shots, smoke from the cigarette in his hand is visible, but shortly thereafter, when Rick puts his arms around Ilsa, the cigarette has disappeared.
After the breakup of the underground meeting, Lazlo is tending his cut on his arm while talking to Rick. Lazlo's shirt has blood on it. A little later, when Lazlo is arrested, there is no blood on the sleeve and the shirt is nicely cuffed.
One of the 'usual suspects' being herded into the Police HQ, an elderly man with a gray beard - wearing black suit, dark tie, white shirt and gray hat - will forty seconds later be seen outside the Police HQ queuing up for an exit visa.
When Victor approaches Rick and asks if they can speak somewhere more private: Ricks handkerchief all night had been sticking out of his pocket by about 1 1/2 inches, but when they're in his office, it's now sticking out at least three inches. AND: All night; Victors handkerchief was neatly sticking out about a half-inch w/ a curved top, but when he & Ilsa return to their hotel room, it's now standing out about three inches w/ a triangular top.
When Victor and Ilsa first go to the Blue Parrot in search of exit visas, the parrot sitting outside is clearly a different bird than the one sitting outside later in the film when Rick comes to see Ferrari.
When Rick first enters the Blue Parrot to visit Ferrari: His hand is stuck casually in his pants, but as soon as the camera changes, it is only his thumb that's hanging in his waistband. In the same two shots; Ferrari's jacket changes from being about 3" open to almost closed.
When the German plane approaches the airport the camera pans across a large group of refugees with their passports lined up outside the Police Headquarters. The camera moves close to the crowd and we suddenly see the individual persons. We see for a second or two a shadow moving across the wall behind them, which is most likely the camera crane.
On the map shown during the movie credits at the beginning, the area where Poland is shown (actually in reality Poland did not exist in 1942, it was politically considered part of Germany or more properly called "Occupied Poland") is in reality parts of Belarus and the Ukraine, which were dissolved into the USSR at the time.
In the initial scene with a map of Africa, Rabat is incorrectly placed at the location of the town of Kinitra and thus is too far north. Rabat is actually about 20 miles further to the southwest at the place where the map indicates a river flowing into the Atlantic. Note that Rabat is correctly placed on the map on the wall in the Prefect's office.
When Renault calls Strasser to tell of the upcoming events at the airport, Major Strasser is in the office of the "German Commission of Armistice" according to the sign on the door. The name should have been in German - or perhaps French, but not in English.
The railroad car Rick boards in Paris is an American railroad passenger car. French railroad cars of the time would likely board from multiple doors into individual compartments. The two cars shown reveal their American heritage in handrails, side moldings and other minor details. Given the unavailability of French cars at the time of filming, the error is understandable.
Near the end of the movie Louie suggests to Rick they go to a garrison just over the border in Brazzaville. It must be quite a walk to the border, indeed, as Brazzaville is roughly 3,000 miles (4.800 Km) and several countries from Casablanca. Incidentally, "Brazzaville" was considered a title for a sequel to Casablanca.
Ugarte tells Rick about the "letters of transit signed by General DeGaulle". Since Charles DeGaulle was the Free French leader and the movie takes place in a Vichy France colony, letters signed by DeGaulle would have been meaningless.
There is a French tricolor with crescent and star in the middle waving over the Police offices at the beginning of the film. Such flag was never used in Morocco. During the time of the French Protectorate the flag of Morocco was the same as today, red with a green pentagram in the middle. The civil ensign used between 1923 and 1956 added a small French tricolor in the canton but never a crescent and star.
In the last scene, a bottle of Vichy water is thrown in the dustbin. The label on the bottle is written in English. It seems unlikely that in a French protectorate, under German control, water bottles were sold with English labels.
We see in the Paris scene that all traffic drive on the right, but when the scene changes to Rick driving Ilsa, the steering of the car is on the right side. France is the right traffic country, the steering wheel should be in the left side.
During the flashback scene in Paris, loudspeaker trucks are shown with the Gestapo telling the Parisians not to act when the Germans arrive tomorrow. In fact, Paris issued no warnings about the German advance at all. The German blitzkrieg overwhelmed the French so completely that all communications were either stymied or went astray.
At the start of the final airport scene, the weather report that is telephoned to the radio tower visibility is quoted as being one and one half mile, light fog, but if the visibility is 1½ miles then it is called haze rather than fog. And the weather report is missing some very important items such as wind direction, wind speed, and air pressure.
Captain Renault boasts that "I was with them [the Americans] when they blundered into Berlin in 1918." The "Great War's" (WWI) Armistice - that which ceased hostilities, was effective November 1918 but it did not end the war. It did however reestablish the borders back to those at the moment just before the outbreak of war. In other words, the Armistice caused the Germans to retreat from France but never ceded any part of Germany to be occupied by "foreign troops." Sometime later - almost 8-months - the peace was concluded among all but the Americans. The US Congress rejected the Treaty of Versailles and actually the USA didn't conclude a separate peace with Germany (The Central Powers) until the start of 1923 - over 4-years later. While the US may have maintained a 'handful' of troops on the continent after the Armistice, there is no record of them singularly or in concert with their allies ever marching through the streets of Berlin - until 1945 that is.
In opening sequences when Major Strasser arrives in Casablanca by plane, the aircraft depicted is an obvious model of a single engine Fokker F.VII transport, a major Dutch designed airliner famous from the mid 1920s. The Nazis had one of the most advanced Air Forces in the late 1930s to early 1940s when this film takes place and Strasser would have likely arrived in an all-metal Junkers trimoter. The F.VIIs, which were made of wood, metal tubing and fabric covering, were upgraded to trimotor configuration in the mid-20s while single engine variants(as seen in this film) were still in service mainly in Europe. A later larger version called the F.10 also made of wood and fabric crashed in 1931 killing Notre Dame football coach Knute Rockne. The F.VIIs and their later variants were taken out of service nearly around the world and replaced by all-metal transports ie the DC-3 and in Germany Junkers all-metal designs. While it's not impossible, it is improbable that the advanced nature of German aviation would have been using an outmoded Fokker F.VII as a transport in 1942.
When Rick is getting drunk he ask Sam, "It's December 1941 in Casablanca, what time is it in America?" He then goes on to say that they're probably all asleep, all across America. However, Rick is not referring to the actual time (noted by giving a month and year rather than a time) and is actually making reference to, in pre-Pearl Harbor America, most Americans are "asleep" when it comes to the war and fighting the Axis powers. This is an intentional attempt at a poetic reference, not a statement of fact.
Just after the scene where Ugarte gives Rick the "letters of transit", Sam is playing "Knock on Wood". The drummer isn't actually playing the drums, but just imitating drumming along with the tempo of the song. The actual audio does not have any drumming in the music during that time. At the actual knocking, his hand moves to the drums or the other stick (not clear, since that portion of the screen is not well lit) and strikes thrice to accompany of others knocking on the table. This can be observed multiple times.
At the very beginning we see a turning globe as a voice describes the plight of those fleeing the war. As the globe turns, we can see across the Soviet Union the words "Union of Socialistic Soviet Republics." Although it was not used as frequently as "Union of Soviet Socialist Republics," it is an accepted translation of the name and occasionally appeared on maps of that era.
After police break up underground group's meeting and Laszlo escapes to Rick's café, Laszlo is trying to bandage his arm with a dish towel. The towel falls off several times yet there is no blood on it.
The goof items below may give away important plot points.
When Rick tells Louis to make out the transit papers in the name "Mr. and Mrs. Victor Lazlo", Ilsa moves toward Rick with her mouth moving. She is obviously saying, "Why my name?" which is the line she delivers in the next shot.
When Major Strasser is shot, five men drive up in a municipal police car. Two men are wearing black caps, and three are wearing white caps. After Captain Renault tells their leader to round up the usual suspects, you can now see FOUR men wearing white caps AND there is a completely new character wearing mechanics clothing standing by Major Strasser's car. This new character ultimately drives off in the Major's car.
In the roulette scene,the man places 6 chips on number 22 and wins. This bet pays 35 to 1 and he should have won 210 chips (in roulette, an individual player's chips are all the same denomination) but the dealer only gives him 3 stacks of 20-30 chips. He bets all of the chips on 22 again and wins. This should have paid 7350 chips (210 x 35). When Rick asks the dealer how they were doing, the dealer tells Rick "a couple of thousand less than we were" when actually they would have just lost 7350 chips of whatever denomination they were.
The fact that Louis' fake phone call to the airport fools Rick shows that the letters of transit are meant to be used as exit documents. Yet in the end, the Laszlos board without anybody ever checking the documents. If once Louis was a hostage he could get the Laszlos around any exit check, why did Rick insist on the letters of transit being filled out? He did it to make it "even more official"; the Laszlos would be protected in case there was an unexpected document check later, either on arrival at Lisbon, or at Casablanca if someone else arrived on scene and events did not continue as planned.
As Major Strasser gets shot, he falls down holding the telephone handset-the telephone cord between the phone and the handset is not connected. However, he actually got a hold of an operator and requested to speak to the radio tower. The phone was successfully operated earlier when the weather report was phoned to the radio tower, the cord is clearly connected-and the phone works.