Continuity mistake: After Andy and Floyd talk outside the grocery Floyd gets into his car with the convict, and when they drive away we see all the food ads taped to both of the store windows while Andy's on the sidewalk, but when it cuts to Andy's closeups the taped ads have changed.
Audio problem: After the mayor tells Andy that his three daughters will be in The Beauty Contest, Andy phones Ellie and when she hangs up on him we hear Andy say, "Hello? Hello?" but we see him only mouthing the second hello.
Mayberry Goes Hollywood - S1-E13
Visible crew/equipment: Near the end, after the producer tells the townspeople to get back to normal and out of their trick or treat outfits, when the crowd disperses we can see some curved chalk lines on the ground near the producer's feet, to mark actors' positions.
Plot hole: When Barney's telling Andy about the poem written on the bank wall, Barney blames Opie and doesn't mention anything about Opie using chalk, but when Opie walks in Andy tells him, "Barney says there's a poem written on the wall of the bank, and that you were standin' along beside it with a piece of chalk in your hand," and then in a few moments Opie explains that some big kids pushed the chalk into his hands. So it's impossible for Andy to have known that chalk was used to write the poem, and not a marker, a pen, or a pencil.
The Keeper of the Flame - S2-E14
Continuity mistake: When Andy holds Barney by the shoulders while congratulating him for an outstanding job of detective work, Andy holds his notebook in his left hand, but when it cuts to a different angle the notebook's suddenly in Andy's right hand.
Ernest T. Bass Joins the Army - S4-E3
Revealing mistake: When Barney picks Andy up and they get back to the courthouse, they find Ernest T out of the jail cell again and breaking more windows, and in the shot of Ernest T leaping in the air we see it's actually a flipped shot - note the backwards "snack bar" in the window (that store is later when Ernest T tries to break the new glass for the courthouse).
The Darlings Are Coming - S3-E25
Visible crew/equipment: After Charlene tells her father that she just wants to look at the pretty man (Andy), when she gets back in the pickup truck we can see the reflection of the moving boom on the windshield.
Continuity mistake: In the initial episode, and Runaway Kid in season 1, Barney is a cousin of Andy's. In subsequent episodes, they are unrelated.
Revealing mistake: The jailed criminals take the key and open the jail cell door. The problem is the dead bolt never moves with the key, showing the door was never locked to begin with.
Revealing mistake: In the scene where Andy starts reading Opie a story, watch when the first woman rings the doorbell. As soon as Andy opens the door you can see that the set all of a sudden gets a lot brighter, as if they turned more lights on.
Visible crew/equipment: When Andy and Barney are in the squad car talking about the crooked stop sign, in both of their closeups we can see the black tape that had been applied to the chrome trim of the squad's windows, presumably to prevent reflections. That tape is gone from the driver's side when they park in front of the courthouse.
Aunt Bee's Medicine Man - S3-E24
Continuity mistake: Andy and Barney are playing checkers near the end of the episode. Andy can be seen making 2 moves in a row, skipping Barney's move.
Continuity mistake: About 20 minutes in, Barney knocks the announcement bell off the door trying to sneak out of the pharmacy, Andy comes in one minute later and the bell rings when he opens the door. You can see the bell swinging above the door.
Other mistake: At the beginning of the series, Hope Summers' character is called Bertha Edwards. Later in the series she is Clara Johnson; still later she is Clara Edwards.
Goober Takes a Car Apart - S5-E17
Factual error: Halfway through the show, Goober takes the motor out of the car and they start it up in the Sheriff's office. If you look at the direction of the fan, it would be blowing the air forward instead of towards the rear of the engine. It would be fighting the air coming through the radiator instead of pulling it.
Continuity mistake: Otis is in the jail and can't sleep. He ask Andy for some water. Andy gets up, unlocks the door and then closes it again (clearly leaving the key in the lock). He comes back a few seconds later and the key is gone and back on the wall. (00:05:05)
Barney Hosts a Summit Meeting - S8-E21
Continuity mistake: In the scene where the meeting participants are in the kitchen, the Russian guy opens the icebox, does not close it, and sits at the table. When Aunt Bee comes in immediately thereafter, the door is closed. She opens it again and partially closes it; but in the next shot, it is fully open.
Suggested correction: The first part of the mistake is correct. However, after Aunt Bee partially closes it, if you keep your eyes on the left side of the screen where the ice box is and watch carefully, you can see the ice box actually bounces back open fully on its own.
Continuity mistake: At the beginning of the show, Barney and Andy are sitting inside a 1964 Ford patrol car. When they are shown up close inside, you can tell it is not the likeness of the same car. The back glass windows look more like a 1960 model possibly. It is definitely not a 1964.
Other mistake: Barney's cousin is coming to Mayberry but gets off the bus in a previous town and misses it. Barney and Andy go out to find him, leaving from Mayberry. They are driving down the road when they come upon his cousin. The cousin is walking in the same direction as Andy and Barney are going, which would have meant he was walking away from Mayberry when he should have been walking towards it.
Other mistake: Helen is sitting on the first base side, there is a play at the plate and Opie is called out at the plate. Near the end of the show, Helen has a picture she took of the play and it show Opie to be safe. The picture angle is taken almost directly from home plate and at a low angle. The backstop is also blocked half the way up. She would have had to be on the field behind home plate for such a picture. It's also very close up but the camera she is using doesn't have any zoom feature.
