Other mistake: When Barney and Andy find the trailer that Malloy's hiding in with his partner and Horton (who's tied up), the other trailer that Andy and Barney are standing behind has license plate "DC 269," the same as some other vehicles in previous episodes.
Visible crew/equipment: Right after Mrs. Williamson leaves the barbershop upset about the carp killing, when the mayor says that they have more important things to talk about - which is the celebration, we can see the curved chalk actor's marks where Williamson had been standing.
Other mistake: The radio communications consoles on the side desk in the courthouse have a few pieces of black tape covering their brand name (though we know it's Motorola from the visible "M" logo).
Visible crew/equipment: When Barney's reading the Sunday comic strip Andy comes in to close the jail in the courthouse, and when Otis walks out of his cell we can see the actor's chalk mark on the floor where he stands.
The Farmer Takes a Wife - S2-E13
Other mistake: At the end, when Joe Waters parks his car in the sheriff's parking spot his car's license plate number is "DC 269," which has been seen in earlier episodes on other vehicles.
Visible crew/equipment: When Barney and Floyd are spying on Sam while he's getting groceries, we can see both of the grocery store's windows and its clear glass, but when Sam drives off the left display window has been covered with a matte dulling spray resulting in an uneven matte surface, to prevent the camera and crew's reflections.
Deputy Otis - S2-E31
Other mistake: Upon arriving at the courthouse, Andy and Barney discover they don't have their keys to get in so Andy decides to go knock on the window at Otis' cell, which he does to wake Otis. However, Otis' cell does not have a window, only the adjoining cell does. (00:20:00)
Suggested correction: Otis' cell does have a window. In the previous episode with Barney's cousin, Barney's pulls the window out of the wall to get Otis out. Also in another episode Barney gets an intercom and places one part by the window to demonstrate how it would work.
It has a window but no glass. It shows Andy knocking on the window to wake Otis up but then it shows him hanging on the bars.
The Arrest of the Fun Girls - S5-E28
Character mistake: Barney states when the Fun Girls were in town before, in Season 4, Thelma Lou didn't speak to him for 10 days. That's not true, they made up the same day.
Revealing mistake: When Barney and Andy are searching the woods for an escaped con, they stop to rest and you can see the light level of the woods go up and down as the crew tries to adjust the reflector screen for the desired lighting.
A Black Day for Mayberry - S4-E7
Plot hole: About 2/3 through the show Barney is locked inside the armored car and Gomer puts about a gallon of gas into the gun port onto Barney's shoes. After Gomer is told of his error, Barney stays inside the truck. The fumes would have killed him, not to mention the risk of explosion.
A Black Day for Mayberry - S4-E7
Character mistake: When Opie comes in at the beginning of the episode and asks where Andy is, the exchange ends with Barney asking "Something you want to see him about?" and Opie replying "No, I'll wait," which makes no sense in context. It would have made more sense if Barney had asked "Do you want to leave him a message?"
Continuity mistake: Aunt Bee won a garbage disposal in "Aunt Bee on TV" and it's one of the gifts she keeps, but she buys another one in a later episode, "Lost and Found," with insurance money.
Character mistake: Mr Darling says there are only 5 strings on the guitar he hands to Andy. You can see all 6 strings when the camera shows Andy playing Dooley.
Character mistake: In the first scene of the show, Andy, Opie and the mayor are on a pier fishing a lake. They are casting with deep sea reels. If you've ever tried casting with a deep sea reel, it doesn't work out well. You can see there no equipment on the poles.
Character mistake: Barney claims he would be losing $3478 on the real estate deal not going through. Considering the houses only were selling for that amount or less there is no way he was making that amount of money on 5% commission.
Suggested correction: I have no idea where you got the idea the houses were being sold for less than $4K. In the beginning Barney says Andy could get $24,000 for his house and $27,500 for the Williams' house (which is also how he got the figure that Andy can get into the Williams' house for $3,500, that's not the price of the house). Those 2 houses alone are $51,500 and 5% would be $2575, and he was losing out on 2 more houses.
That has bothered me forever! I thought the house Andy was thinking of buying was 3500 not 35000! Now the amount of commission makes sense although 35000 is LOT for a house in North Carolina in the early 60's! Thank you for clearing that up.
Just watched that episode and yes, you are correct on the math. But my problem is, new houses in this era were around $8000 - $8500 new, so these older houses would have been worth nowhere near $24-$27k.
Deliberate mistake: Luke's dog in the episode is the same dog used in other episodes involving a dog in the plot.
Continuity mistake: At the end, when Aunt Bee serves dessert her spoon and napkin are on the table, but in the next closeup of just Andy and Opie her spoon and napkin have vanished, then when Bee's seated she removes her napkin and her own dessert and spoon should still be on the table, but in the closeups of Andy and Opie they're not.
Continuity mistake: During the scenes at Wally's station, the two prop gas pumps each have just one fuel dispensing hose/nozzle which switch between being between the two pumps, or with their hoses/nozzles on the opposite side of the gas pumps.
Continuity mistake: On one occasion when Mr. Weaver leaves the courthouse to walk around the building to look in through the cell window, he goes in a counterclockwise direction. However, when the scene switches he is approaching from a clockwise direction.