Visible crew/equipment: At the mill, when John tells Buck that Willie Brimmer might be at the Montgomery cabin with Jim-Bob, in the next closeup of John we see a billowy trail of cigarette smoke at the bottom right corner of the screen, but the only people standing there are Elizabeth, John, and Buck, and none are smoking. Presumably, it was someone offscreen smoking too close to the camera (similar to a mistake in 1978's "Halloween"). (00:26:05)
Factual error: When Elizabeth asks Zeb how Vanessa can be happy, Zeb has his old catalog with a bunch of flower seed packets on his lap, and as they both hold up the packets, particularly Elizabeth, the modern Universal Product Codes are at the back of the packets. The UPC did not exist until many years later. (00:10:05)
Visible crew/equipment: When Jim-Bob delivers Betsy's mail she's washing her hair outside, and as she flips her wet hair back we can see the microphone under her halter top, while her arms are up. Then when she walks toward the cabin with Jim-Bob, the bulge of the mic transmitter is visible at the back of her shorts. (00:06:20)
Visible crew/equipment: While the family starts packing up their car with John's suitcases and boxes, right after John says, "I just don't want any kind of a big scene," a cluster of boom mics dip into view and stays there at the top of the screen, over Mary Ellen and Jason. Then in the closeup, as John agrees that they will all go see Olivia, a crew member wearing a blue shirt (with a front pocket) is visible in the vehicle's window reflection. (00:44:40)
The Recluse - S6-E3
Visible crew/equipment: Near the end, while John is working alone in the mill Ben shows up, and when Ben asks, "Need some help," a crew member is hiding behind the stack of drawers, toward the right side of the screen. It's not Zeb or Easy or any family member. (00:46:30)
The Search - S4-E15
Continuity mistake: When John borrows Vern's blue car to search for Olivia and the kids, its license plate number is "45-2678" in wide shots, but when John-Boy spots their truck at the side of the road John stops short, and the license plate number is "84-6209" in the closeup. (00:17:10 - 00:18:45)
The Reunion - S1-E14
Visible crew/equipment: After Miss Emily tells her sister to serve some more Recipe to Homer and Zeb, when it cuts to the Walton house the set's c-stand lighting equipment is visible at the left side of the screen. (00:15:45)
The Bicycle - S1-E23
Factual error: While Ann is on the Walton's swing telling Curtis that he deceived and lied to her, when Curtis gets back into his car, a modern vehicle is visible at the right side of the screen, which is inappropriate for the time period. (00:46:10)
The Scholar - S1-E22
Visible crew/equipment: When John drives off with Olivia and Esther while everyone shouts their goodbyes, just as we hear, "Have fun!" a director's chair is visible at the right side of the screen. (00:11:50)
The Thanksgiving Story - S2-E10
Other mistake: During John-Boy's entrance exam at Boatwright University, when he's given the pamphlet and history test questions, note three of the questions include the contraction "it's" which is incorrect within those given questions. Each question should have used "its" without an apostrophe. Additionally, the sign on the University's wall reads "keep your eyes on you own paper" instead of "your own paper." (01:00:35)
Other mistake: While John and his sons are at the pig pen talking about Rover, in the first wideshot facing them all we can see the Baldwins' stationary car parked near the pen, waiting for the cue to move at the proper time. During their entire conversation nobody remarks or reacts to the Baldwins' car being right there, not until the second wideshot, just as the vehicle moves closer to the Walton house, and then everyone exclaims, "Baldwin sisters/ladies!" as if they just now showed up. (00:03:55)
Visible crew/equipment: When John-Boy is on his way to Boatwright and Polly flags him down, just as John-Boy pulls over and then backs up, the reflection of the location's 9-light par bank lighting is visible on his car's windshield. (00:10:55)
Visible crew/equipment: After John finishes checking on John-Boy's car, when it cuts to the kids in the bathroom, note the vanity mirror's reflection. In between Mary Ellen's and Jason's reflections, we can see an older man wearing black glasses, yellow shirt, and blazer, who is standing outside the bathroom's doorway. We continue to see the reflection of this crew member in the mirror when Jim-Bob and Ben go at each other. (00:04:25)
Visible crew/equipment: When John-Boy falls off the ladder and breaks his wrist Zeb drives him to the doctor in the truck. During their drive we can see through the window behind them, and there's a crew member wearing a red shirt riding along in the back, as they drive past a parked 1970s station wagon. The camera and its operator are casting a shadow on Zeb as well. (00:18:25)
Visible crew/equipment: When Judge Thornbury fails to convince John-Boy to kill the story on his car accident, Thornbury heads over to talk to John at the mill, and just as Zeb says, "Hiya, Judge," the boom mic pops up into view at the bottom of the screen. (00:17:40)
Visible crew/equipment: After Jason tells John that he left word with Ike for the Sheriff, Elizabeth runs into the barn worried about Pete. Then Gino walks over to his T-mark (plastic type) on the dirt ground and a second T-mark (partially covered in dirt) is beside it. Soon, John-Boy walks over to that second T-mark as he glances down to presumably be certain he hits his mark. (00:32:55)
The Carnival - S1-E3
Factual error: After John-Boy reads the scary bedtime story to Jim-Bob and Elizabeth, when Elizabeth is lying in bed she's holding her Raggedy Ann doll, and in the closeup we can see the doll's Knickerbocker tag. This episode takes place in 1933 (the Chicago World's Fair is mentioned at the end), and the Knickerbocker Toy Company created this doll in the late 1960s. (00:09:30)
The Secret - S4-E16
Visible crew/equipment: After Jim-Bob finds out of the truth at the Hall of Records, when it cuts to Godsey's the two white tape marks are visible on the floor where Ike places the long grabber tool, as well as the two black tape marks where Esther and Ike will stand. (00:37:20)
The Burnout - S4-E18
Visible crew/equipment: After Olivia tells Erin to try being Erin Walton again, when it cuts to the boarding house a white tape mark is visible on the rug, where Mrs. Brimmer is about to stand. (01:26:40)
