Visible crew/equipment: At the end when Aunt Bea enters the courthouse, she doesn't close the door completely. You can see a hand from outside grab the door, and close it very slowly. (00:23:20)
Mayberry Goes Hollywood - S1-E13
Continuity mistake: Barney's fancy new uniform has a badge on it when he first models it for Andy. During the ensuing festivities, it's missing.
Aunt Bee's Medicine Man - S3-E24
Continuity mistake: The pillow on the right side of the couch is there while Opie is talking to the Colonel. When Andy walks around after Opie leaves, it has suddenly disappeared. (00:16:00 - 00:18:00)
Factual error: December 25, 1960 was on Sunday. The calendar in the jail house shows a calendar (which has been used in other episodes) with Christmas Day on a Friday. (01:30:00)
Opie's Group - S8-E9
Audio problem: The band Opie is in has two guitar players but no bass player, even though you can hear a bass guitar being played.
Other mistake: When Barney is ready to pour the plaster cast into the shoe prints, there are only a few prints on the ground. There should be a continuous set of prints from the barn door to wherever.
The Gypsies - S6-E23
Factual error: The Gypsies manage to operate a shortwave radio without an antenna or AC power.
Continuity mistake: When Otis makes up a poem about jumping rope, Barney lets go of the rope and Andy is left holding the other end while the rope is left stretched across the floor. One second later when Opie and his friend come running in, Andy is now holding the rope in his other hand all rolled up.
Revealing mistake: The woman in the foreground, as the siren is stuck, is carrying a paper grocery sack from "Hollywood Ranch Market" which was located on Vine St and Fountain Ave in Hollywood, Los Angeles. (00:09:35)
Factual error: We know from 2 episodes prior (Man in a Hurry) and generally mentioned throughout the show, the only filling station in Mayberry is Wally's Filling Station. In this episode Mayor Stoner is accused of only putting the new underpass in Mayberry because it will be next to Mayor Stoner's brother's filling station.
Continuity mistake: The fuel pumps at Wally's gas station (regular and super) switch sides between numerous episodes.
Plot hole: When Barney and Andy are on the street watching the window painter, Andy looks over and says "I believe that's Briscoe Darlin's truck!" - but when they were driving up to his place the next morning, they both got out of the car and were wondering where their house was they heard music playing. The next scene shows them pulling in - seems that if he was able to recognize the truck in town, he would have been able to recognize the truck and they could have drove around looking until they found it?
The Merchant of Mayberry - S2-E22
Plot hole: In the episode where Barney confronts the two farmers for selling produce on the side of the road, Barney mentions that they're not allowed to sell because of "section 17.4" of the ordinance code - that street vending is not allowed, and Andy confirms it. But in this episode Bert comes to town and is selling dry goods, etc. and he's allowed to sell. Even Ben states that there must be a structure if he's selling - wouldn't you think that Andy and Barney would have known that already before setting him up to sell?
Andy and Barney in the Big City - S2-E25
Factual error: Though they are suppose to be in Raleigh, the skyline view is not Raleigh, NC.
Factual error: Andy tells the hobo "that will be the 3:45 stopping for water", meaning its a steam locomotive, but by the time this episode was made railroads had long since switched to diesel.
Continuity mistake: At the beginning of the show, Andy notices a wanted poster on the office bulletin board and tells Barney that he had learned from news accounts that the wanted person had been captured. Barney removes the poster and places it in a file cabinet. The next day when Roger reports for duty, he and Barney are looking at the bulletin board and the wanted poster is back up.
A Black Day for Mayberry - S4-E7
Factual error: An armored truck is going to Fort Knox from Denver would never go through Mayberry. Fort Knox is in Western KY south of Louisville on I-65. NC is accessible mainly by going south down I-75 to Knoxville, then heading South East along I-40 towards Asheville, NC. To get to NC from Fort Knox you would need to go up to Lexington then Knoxville/or go east across the wky fka The Green River pkwy to I-75 then to Asheville. There is no easy route; why would they go through KY to NC and turn back to KY?
My Fair Ernest T. Bass - S4-E17
Character mistake: During the party at Mrs. Wiley's, Ernest Bass' girlfriend is called "Ramona." At the end of the show, Ernest T keeps calling her "Romina".
Goober Takes a Car Apart - S5-E17
Factual error: How in the world did Goober lift that heavy motor out of the car?
Barney and the Cave Rescue - S4-E13
Plot hole: Andy and Helen go into the cave and there is a cave in. They find their way out and go into town to change, when they hear on the radio that Barney is getting the townsfolk together to form a rescue, Helen and Andy go back to the cave so barney can rescue them. This makes absolutely no sense. Once they get out of the cave why didn't they go back to tell Barney they were out, why did they have to flag down a truck for the ride back into town? Did they get to the cave with the squad car? It's hard to believe nobody saw them back in town, and how did they get to the cave?
Answer: It was a joke. They were supposed to be dumb hillbillies.
Both. According to later interviews with both Andy and the Dillards band (the real name of the band that played the parts of the Darling children, of which Charlene (Maggie Peterson - Mancuso was also a member) the reason the Darling boys never had any lines was because they would've had to have been paid if they spoke. In return for appearing without lines or pay, Andy promised to get as much of their music onto the show as possible which, he did. This obviously gave them a lot of exposure.