Revealing mistake: When Deacon tries the doors on the van, the wall moves, revealing it's not a van but a set. (00:08:30)
Mammary Lane - S5-E5
Continuity mistake: At the beginning of the episode, the establishing shot shows a bowling alley with a sign that reads Mar Lin Do Lanes. A few minutes later, Doug welcomes Denise on behalf of the family at Bowl-O-Rama. (00:04:10)
Window Pain - S5-E2
Visible crew/equipment: When Doug gets into their Jeep after meeting the new neighbours, a man and the backstage can be seen in the passenger side mirror. When the shot cuts back to Doug again it's darker but when he backs up, the reverse lights of the Jeep reveal the man and stage again. (00:26:55)
Revealing mistake: In the final scene of the episode, Arthur is searching for used bottles of nasal spray. He empties the contents of the trash can on the kitchen floor and finds one after sifting through the trash. However, the bottle had already been positioned on the floor next to the trash can before he picked up the trash can so it would be easy to find when the trash was emptied on the floor.
Continuity mistake: When Carrie is starting her new work position, her bag on the desk behind her moves without anyone touching it. (00:04:20)
Mammary Lane - S5-E5
Visible crew/equipment: When Denise is running away and Doug is on the floor, a camera shadow is very clear on Denise's car. (00:21:30)
Visible crew/equipment: When Carrie hugs Doug and wishes him good luck, you can see the battery pack for her mic in her jeans. Clear as day. (00:17:35)
Visible crew/equipment: Just as Arthur walks in on a mobile phone, a boom mic is visible at the top of the screen. (00:04:00)
Continuity mistake: When Doug asks Carrie to take a photo of him on the bed, there is nothing on the bed. After she says "stop", 2 items have appeared on the bed that were not in the previous shot. (00:08:45)
Continuity mistake: The leaflet in Carrie's hand at the start vanishes instantly. (00:03:10)
Window Pain - S5-E2
Revealing mistake: When Arthur jumps over the turnstile at the subway where Spence works you can see it is a stuntman wearing the same outfit as Arthur. (00:37:15)
Other mistake: Doug says in 4-11 "Repo Man" that he doesn't know when Carrie is in bed or not. However in this episode he states that he can't sleep unless someone is next to him. (00:01:10)
Continuity mistake: When the IPS guys are discussing the Superbowl party, one of them takes a drink. He then lowers his can. When the angle changes, the can has changed hands. (00:04:20)
Continuity mistake: When Tim asks Doug if he wants to tee off back at the start of the hole rather than halfway down the fairway, he is pointing with his golf club. Camera cuts and he isn't. (00:15:35)
Character mistake: The woman in the store claims that the umlaut on the shoe size indicates a half size in Europe. This is wrong because the European shoe size system (used in Germany among others) is completely different from the US system. Carrie's 6 1/2 shoes would be a size 39 according to the European system.
Taste Buds - S5-E24
Continuity mistake: Just after Carrie tells Doug that she knows what he has been doing, she storms out of the kitchen. Doug has his hand on a water bottle on the table, then picks it up as he rushes after Carrie. In the next shot of Doug walking into the living room, the water bottle is gone.
Continuity mistake: When Carrie takes the first lot of Hofferman's pictures off Doug, she's holding them portrait. Camera cuts and she's holding them landscape. (00:05:30)
Continuity mistake: When Doug and Carrie are told that mold isn't covered by their insurance, Doug has his fist clenched by his mouth. Camera cuts and now it's open palmed and on the side of his head. (00:01:00)
Continuity mistake: When discussing the Superbowl at IPS, Danny has a roll in his hands. Camera changes and he picks it up again. (00:04:30)
Revealing mistake: When Carrie knocks the cards over at the start, some stay in the pyramid shape despite being knocked over, revealing the cards are glued together. (00:03:15)
Answer: Sara hasn't been mentioned in later episodes, and it suggested in later episodes that she never existed, and that Carrie is an only child. Kevin James stated that the producers couldn't think of an good plots to use with Sara, so they left her out.