Your Home Sweet Home is My Home Sweet Home - S4-E25
Continuity mistake: The Petrie house (where Rob and Laura, Jerry and Millie are standing together bickering) is completely different from the episode "Where Did I Come From?" and a few others.
Sally and the Lab Technician - S1-E3
Continuity mistake: When Jamie Farr the "Snappy Service" guy comes in and gives everyone their coffee Buddy throws a straw into the straw cup, but it falls down on the floor then vanishes, never to be seen again.
Never Bathe on Saturday - S4-E27
Continuity mistake: The bathroom door that Rob shot the knob off with the gun is not there in 1 scene, but suddenly reappears a little bit later back on the door, he's able to open and close the door with ease when he is in the bathroom with Laura while she's getting out of the tub. (00:20:30 - 00:22:00)
Your Home Sweet Home is My Home Sweet Home - S4-E25
Continuity mistake: In this episode it is shown that the Petries live in a house with a huge rock in the basement. In the episode where Buddy's brother, Blacky visits "Hustling the Hustler", they play pool in the basement and there is no rock.
Continuity mistake: When Laura tries to read the phone number that Rob scratched out, Rob gives her the number as "New Rochelle 69970," which happens to be the Petrie's own phone number, as noted in other episodes.
The Death of the Party - S4-E13
Continuity mistake: When Laura puts the ice cream in the freezer, the freezer is full, however when Millie brings over the ice they are able to put it in the nearly empty freezer.
The Case of the Pillow - S4-E21
Continuity mistake: In some of the courtroom scenes you can see feathers flying around, before Rob spills feathers all over the courtroom.
To Tell or Not to Tell - S1-E8
Continuity mistake: In this episode Sally asks Rob if he has a brother, Rob says "Yes, but he is married." However his brother Stacy is trying to become engaged later in the series, in episodes "Stacy Petrie Part 1 and 2."
Romances, Roses, and Rye Bread - S4-E7
Continuity mistake: When Sally lets Burt into her apartment, her hand is on her forehead and then all of a sudden it's down by her side.
Continuity mistake: Rob, Laura, Buddy and Blacky are in Robs basement, there is no wine bar, or giant boulder, and the steps that come down from upstairs lead straight up to nowhere. Because there's a window to the left beside the steps, rather than how it was when they were buying the house where you could see into the house. And there's a giant gap under the wall behind the pool table. There's also a random door that leads somewhere also behind the pool table. (00:24:47)
Continuity mistake: The "Staff Writers" door is backwards. In other episodes the door opens up to the right, not to the left. Also the door is a dark color normally, unlike this scene in this episode where it's a light color. (00:19:41)
Continuity mistake: The buildings seen from the window of Rob's office change in different episodes.
Never Bathe on Saturday - S4-E27
Continuity mistake: In the first scene, when Laura tells Millie she spent the whole day in the bathtub and Millie says "In a bathtub" Millie moves from sitting on a chair to sitting on the couch next to Laura in a flash.
The Man from My Uncle - S5-E27
Continuity mistake: When Rob and Harry are in Richie's room, it's bright and sunny outside. Six seconds later, they are in the living room, and it's pitch black outside.
The Sick Boy and the Sitter - S1-E1
Continuity mistake: In the opening scene when Laura answers the phone her hand is on the wall. The shot changes, her hand is now on her shirt.
Fifty-Two, Forty-Five or Work - S5-E13
Continuity mistake: Rob tells Sally, Buddy and Mel "It was rough... Out of work, new house, no furniture, a baby on the way, 1 single dime in the bank!" In several other episodes Rob said they either already had a kid, or they were on their way to the hospital in the cab, on their way to the hospital in the back of a laundry truck, or were already at the hospital. They already had furniture in the other episodes when they brought Richie home from the hospital.
The Sick Boy and the Sitter - S1-E1
Continuity mistake: Richie's room is completely different from this episode compared to the later episode "The Man from My Uncle."
My Husband is the Best One - S3-E14
Continuity mistake: In a different episode the Alan Brady show writers were on a different floor than Alan Brady and Mel Cooley. Yet in this episode they're on the same floor because we can hear Alan yelling at Mell while Rob is in the writers room where Sally and Buddy, currently furious reading the magazine article. (00:14:37)
It May Look Like a Walnut! - S2-E20
Continuity mistake: The episode opens with Rob watching a horror movie on television. The bedside clock shows the time as 9:05. At the end of the episode 23 minutes later, the clock shows 9:10.
Continuity mistake: The number of glass "pea pod" shaped sphere balls change through out the series. In "Don't Trip Over That Mountain" there were only 3 spheres. In several episodes there were 4 spheres and in others there were 5 of them.
Suggested correction: No, the Petries buy the house with the rock, but swap it with their best friends and buy the house next door. Therefore Jerry and Millie have the rock in the basement.
Rob has to pay half the cost for Jerry to seal his basement every year. The reason why is because Rob's rock redirects water that ends up flooding Jerry's basement.
The Petries did buy the house with the rock. At the end of the episode Rob explains how their rock caused flooding in the Helper's basement.