During the opening credits (for Screenplay, Associate Producer and Director), the Hotel Europa Salzburg can be seen in the distance to the left of the Collegiate Church that is in the foreground. The Hotel Europa Salzburg was built in 1957 and is obviously more modern than the surrounding buildings.
When Maria sings "My Favorite Things" to the children during the thunderstorm, the Captain comes in and stops the fun. As she watches the children running into line, she says something like "Wha-" after finishing the song, but her mouth doesn't move.
During most of the song "Edelweiss", Captain Von Trapp appears to strum the guitar appropriately. We hear the song end with a single chord running from the lowest string to the highest, yet he ends by plucking only the first (lowest) string with his thumb.
When Maria and the Captain meet the children after their honeymoon, when the children are telling Maria they are going to sing, Friedrich approaches her and he obviously tells her something but there is no sound of it.
After Maria's wedding there is a sequence of ringing bells. In the last shot of only one deep bell ringing, you can clearly hear the bell ring well ahead of the clapper actually striking the bell's rim on screen.
During the final scene of "Do Re Mi," as the children are jumping up and down the steps, Louisa forgets part of the choreography. She glances at the other children, then tries to correct her placement by moving to another step.
During the wedding of Maria to Captain Von Trapp, "Uncle Max" Detweiler approaches the altar and genuflects (kneels) onto his left knee, rather than the proper Catholic genuflection onto the right knee.
After the Von Trapp family have been stopped by the Nazis after pushing the car out of the gates of the house, and then allowed by Herr Zeller to take part in the music festival, when Maria and the Captain go to the front of the car, he gives her a "cross-fingers" sign. This is the sign for luck in many English-speaking countries (and maybe others too), but in German-speaking countries it is "Daumen drücken" ("press thumbs") for luck, not crossed fingers. If Christopher Plummer really had been Austrian, he would have pressed his thumb down on a vertical clenched fist.
Bandage (covered with makeup) visible on Liesl's ankle in "16 Going on 17" but not in the surrounding scenes (she sprained her ankle while rehearsing part of the sequence, after other parts had already been shot). The bandage has been erased on the DVD.
Every time that the children are all together forming a straight line they manage to keep a straight line of heights, from the eldest to the youngest. But throughout the rest of the film, the five eldest children appear to have different heights from one scene to another.
Prior to singing "Edelweiss" in the drawing room, when Maria first offers the Captain the guitar, he is holding a glass of port in his right hand, he begins to raise his left hand to gesture. The scene cuts to a wider shot and the glass is in his left hand as he raises his right to gesture.
When Maria runs away from the Von Trapp Villa just before the intermission, she's carrying her carpetbag and her guitar, so that means she's taking them with her back to the Abbey. After the intermission, the scene is the children playing ball with the Baroness and then singing a song. Max asks Liesl to get the guitar, and it's the exact same Goya guitar that Maria had. It is highly unlikely me that the Von Trapps just happened to have the same make and model guitar that Maria had.
Captain Von Trapp's car demonstrates a dual personality - at least, the convertible top does. In some scenes (e.g. when the kids drive up to meet Von Trapp after his honeymoon with Maria), his exquisite convertible has a black top. In other scenes (e.g. when the family is caught by the Nazis in mid-escape while pushing the car away from their home), the car has a white top.
The first time Maria goes to see the Reverend Mother, Sister Margaretha tells her she can go in and puts a hand on her arm. She takes her hand away and walks out the door. In the next shot, from inside the Reverend Mother's office, she still has her hand on Maria's arm and then walks away again.
At the party, Herr Zeller meets Captain Von Trapp and the Baroness and then moves on his way. After him are a lady and gentleman who greet the hosts. However, as Herr Zeller is walking away we see the lady and gentleman greet them again over his shoulder.
At the beginning of the movie (just after it tells us we're in Salzburg, Austria), the nuns are shown walking through the Abbey on their way to mass. Two nuns are shown beginning to rise from kneeling in front of what may be icons. In the next shot they are no longer there.
During the thunderstorm, when Gretel runs into Maria's room, she throws open the door and we hear and see it bang on the opposite wall. However in the next shot, a close up of Gretel we see it bang against the wall again in the background but no sound is heard.
When Maria capsized the rowboat full of children prior to meeting the Baroness, the rowboat turns sideways and nearly fills with water, sending two-thirds of the sinking boat under the waterline. Seconds later, the boat only contains about ten gallons of water and is floating safely again.
The outside of the Von Trapp house is clearly not the same house as the inside. The front of the house from the outside has tons of windows on all levels but when Maria walks in the front door there are no windows in the two story foyer - just the giant staircase and a plain windowless wall around the front door from the inside.
When the children begin to sing "My Favorite Things" to cheer themselves up, they hear Maria's voice joining in the singing. As the children hug Maria, she pulls Friedrich's hat over his eyes and he grabs her guitar case, then seconds later his hat is back on top of his head without him adjusting it.
Louisa is standing at the stern (next to Liesl) and Gretl is standing at the bow (next to Maria) of the rowboat before it capsizes. After the rowboat capsizes Louisa swims away and yet seconds later is seen carrying Gretl out of the water.
In the wedding scene as Maria is walking down the aisle she has clearly covered half the distance of the length of the aisle in the first shot. In the next shot she suddenly is in the back of the church again, slowly progressing and passing for the second time the same pillars she has passed just before, in the first shot.
In the 'My Favorite Things' sequence, Friederich's hair color is much darker and closer to his natural hair color than when Maria meets the children the first time earlier in the day. This is because the first scene shot for the film was 'My Favorite Things', before the color bleaching of his hair was completed.
During Maria's 'I Have Confidence' song there is a field with a horse behind her to the right and as she continues singing she goes down a path that puts that would put that field on her right. In the next shot of her singing there is a long building on her right with no sign of the horse or field.
When the Von Trapp family convenes with Uncle Max, after the puppet show, the captain is seen holding his glass in his right hand. The very next, longer, shot shows him holding the glass in his left hand.
When the Von Trapp family is trying to leave their home to escape from Austria, Maria and the girls are following the car as it's being pushed through the courtyard by Capt. Von Trapp, Max and Kurt. Friedrich is steering and he exits the car to open the gates of the estate. As he turns to go back to the car, you can see him step over one of the ropes being used to pull the car off screen as the men push it.
Salzburg is on Austria's German (not Swiss) border. (In real life the von Trapps simply traveled 100 km to the Italian border for a supposed mountain-climbing vacation, crossed openly, and did not return. The border closed the very next day.)
At the beginning of the film where Maria is dancing on the top of the mountain and she hears the bells of the convent ringing, firstly the mountain is so far away that there is no chance that she would hear it, even with bionic hearing. Secondly, she runs down the mountain to the cathedral in minutes when it's about 20 miles away.
When Maria requests the family to "thank the Lord" when they are having their first meal together, she recites the Protestant grace and the Von Trapps pray in a Protestant manner with their hands folded and head bowed. Being a Catholic family, they would have started and finished with a sign of the cross, and the Catholic grace, "Bless us O Lord and these thy gifts" etc.
At the wedding, Captain Von Trapp wears a uniform with 3 gold sleeve stripes and a circle. This is the insignia of a senior lieutenant in the Austro-Hungarian Navy. His sleeve should have had 1 wide stripe with 1, 2 or 3 narrow stripes plus the circle, depending on how senior a captain he was at his retirement.
The Captain and Maria return to Salzburg early from their honeymoon when they hear about the annexation of Austria to Germany. They pull up to their home, and the Captain quickly tears up a Nazi flag that has been displayed there. It is clearly warm and there are leaves on the trees - late spring or summer. The annexation of Austria took place on 13 March 1938, and it would therefore have been colder, grayer, and there would not have been any leaves on the trees.
Georg Von Trapp was an officer in the Austro-Hungarian Imperial Navy in World War I, commanding ships based from ports on the Adriatic coast of Croatia, an Imperial province. In 1918, the Empire was dissolved, leaving Austria a landlocked country, and Von Trapp out of a job in the process. "Austrian Navy" sounds like an oxymoron to viewers unaware of the historical context.
The Mother Abbess tells Maria that Captain von Trapp's wife died "several years ago". A distressing number of people have heard this as "seven years ago" and wonder how she can have given birth to the five-year-old Gretl.
When, on their first day out, Maria asks the children what songs they know. Friedrich responds that they 'don't know any' songs. Later when the guitar is offered to Captain von Trapp and he is deciding what to sing, Friedrich can be heard saying 'sing us something we know'. Given, however, that they haven't had much music for at least 5 years, it's likely some wouldn't remember how to sing, but would still know some songs as they listened to it. The fact that Friedrich asked for "something we know" is, in fact, proof of that.
Liesl tells Maria that she and her siblings do not know how to sing when it shows her and Rolfe singing "16 Going on 17" in a previous scene. However, Liesl is indicated as being a rebellious teen that doesn't want the rest of her family to know (her romance with Rolfe, for instance, isn't known to the rest of them), so there is every chance that she knew how to sing. Besides, being the oldest, she most likely remembers her mother singing.
Do Re Mi. The children learn the song while wearing their play clothes. They are later seen in other clothes then back to their play clothes. However, it is obvious from the various scenes that they are singing this song over the course of several days, hence the clothes changes. The children are shown in other clothes while in town or in the house grounds, while wearing the play clothes climbing trees or in the countryside - suggesting they wear them for activities where they may get dirty (so as not to spoil their good clothes). Additionally if it were the same day, it would be strange for Captain Von Trapp to drive all the way to Vienna to meet Elsa and Max and then drive back.
The claim that an orange crate says "Product of Israel" despite Israel not existing at the time the film is set is false. Though the crate and its label are clearly visible in a publicity still taken during the filming of that sequence, the crate is not visible in the completed film.
When Captain von Trapp and Maria come back from their honeymoon, he pulls a Nazi flag down from above his front door. As he does so, he is obviously searching for the correct place to tear the flag and eventually finds a slit which has been marked by the prop people. You can also see the slit going down into the flag.
When the Nazis are searching for the family on the roof of the abbey, one of the actors shines his flashlight accidentally toward the "mountains," and it throws a beam of light on the painted wall, revealing the fact that the Alpine scenery is painted, not real.
Immediately after 'Do-Re'Me' as the children finish their stair run, you will see Kurt trip slightly on the stair. As the camera fades away, the actor can clearly be seen looking at a crew member (possibly the director) and grinning sheepishly as if recognizing his mistake.
When Maria and the children come back from their day of play and are singing inside, they decide who is next to sing; Captain Von Trapp. When Maria hands the Captain her guitar, it has no strings on it. While he is playing and singing, the strings will appear then disappear.
When Maria is singing "My Favorite Things" to the children the first time, during the first verse and chorus, one of the girls, Marta, is seen miming the words to herself - especially the last line of the chorus, "... so bad!"
The exterior front door of the Von Trapp villa, shot in Salzburg, is a double door, maybe 7ft high, with a semi-circular glass fan-light above it. The interior of that same door, shot at Fox's studios in California, has a similar double door below, but with double height solid wood paneling continuing above it. No fan-light to be seen anywhere. It's interesting to note that the back door of the villa, opening onto the rear terrace, and again seen at various points during the movie, is also a 7ft high double door with a fan-light above it, but the interior and exterior versions of this do match up.
During the opening credits, watch very closely at the bell tower. Sometimes you see a full complete swing on the bell and sometimes the bell appears to have hit a brick wall and suddenly reverts back the other direction only completing a half swing.
During the thunder storm, when Liesl supposedly climbs up to Maria's room, we see her outside, running over to the window. She then tells Maria she climbed up. She could have climbed up elsewhere and made her way along a ledge, but when we look outside there's no evidence of a ledge wide enough to facilitate her running.
When the Nazis are searching for the family when they are hiding between the wall and the tombstones, one shines his flashlight through the locked gates. When the shot goes to the light panning around the enclosures, the beam is not that of a flashlight, but of a spotlight (non-defined edges, lighter/darker parts of the beam, vs. defined edges, bright circle).