Deconstructing Carrie - S7-E15
Continuity mistake: While Carrie was being harassed by the construction workers, Doug was watching by looking out the door to the right. In the next shot, you see Carrie through the window, coming in from the left.
Continuity mistake: The garage door in the outside view has 4 windows. Switch to the inside scene and it has 3.
Mean Streak - S4-E3
Visible crew/equipment: Doug is debating smashing the woman's parcel. As she opens her door a black tape marker is visible on the floor. (00:15:50)
Food Fight - S4-E13
Continuity mistake: When Spence and Becky arrive near the end, Doug's coat on the floor changes position with no-one touching it. (00:17:20)
Food Fight - S4-E13
Continuity mistake: When Doug is checking the mail while telling Carrie about checking the food twice a week, the letter at the back of the pile is red. Camera changes and now it's a normal envelope. (00:05:30)
Visible crew/equipment: In the church just as the minister tells Doug and Carrie to take a seat, two white tape markers are visible on the red carpet. (00:05:30)
Continuity mistake: When Doug is speaking to Spence and Deacon about Carrie throwing up, Spence takes the cap off his beer which reappears a few shots later. (00:02:45)
Visible crew/equipment: When Doug says he doesn't want to look after Arthur in the bedroom, there are 4 tape markers visible on the floor at the foot of the bed. (00:14:30)
Continuity mistake: When arguing with Arthur about moving upstairs, Carrie has her hand on a chair or the table depending on the shot. (00:05:50)
Continuity mistake: Arthur throws Doug's pumpkin out near the start and there is no pumpkin on the floor in the kitchen. A few minutes later in the scene, there is pumpkin on the floor in the kitchen. (00:03:40)
No Retreat - S4-E5
Continuity mistake: When Horseback riding Doug is holding on to the straps with either one or two hands depending on the shot. (00:16:50)
Continuity mistake: When Deacon is asking Doug if "Chain of causation" is a legal term, him arm goes from straight to bent between shots. (00:17:20)
Other mistake: Carrie says that Deacon doesn't drink or smoke. Many episodes have shown Deacon drinking a beer or a margarita.
Wish Boned - S7-E17
Visible crew/equipment: When Doug starts to walk over to the flight attendant, a second camera slides into the shot for a few seconds to the right of the screen. (00:12:36)
Visible crew/equipment: When the camera cuts into the wide shot of Carrie leaving the store, the camera rig to the left of the screen is almost entirely visible. You can see it follow Carrie around for a good 10 seconds. (00:10:35)
Mean Streak - S4-E3
Visible crew/equipment: After giving an interview Doug walks over to Deacon and a tape marker from earlier in the scene is visible on the floor. (00:05:20)
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.