Mr. Monk and the Candidate (1) - S1-E1
Continuity mistake: When Mrs. St. Claire refers Mr. Monk as "Rain man", her glass is about an inch and a half full. Next time we see her the level of liquid has dropped. (00:16:45)
Mr. Monk and the Candidate (1) - S1-E1
Factual error: When the rifle is identified as a "Weatherby Fibermark", Monk and Randy say it's a British rifle. But Weatherby is an American company.
Mr. Monk and the Candidate (1) - S1-E1
Character mistake: When Captain Stottlemeyer is saying that the two murders are unrelated, he says, "He was stabbed, she was shot," when the truth is the exact opposite.
Mr. Monk and the Candidate (2) - S1-E2
Other mistake: When Monk is climbing the ladder to pursue the killer, at a couple of points, he wipes a rung, then grabs the one above it. (00:18:15)
Mr. Monk and the Psychic - S1-E3
Plot hole: When Monk is looking for the pebble, he immediately makes an announcement through the shop's speaker system and then directly asks the guy wiping the floor where the rest of the garbage is. Given the size of the trash can it is not realistic that the guy wiping could have filled the trashcan, emptied it and have it filled half again in the 2 to 10 minutes that might have passed since the pebble got lost.
Mr. Monk Meets Dale the Whale - S1-E4
Revealing mistake: When Monk is showing how Dale and his Doctor murdered the judge one can see that the knitting of the right chair is already cut to ensure that the policeman will fall through it when he later steps on it.
Mr. Monk Goes to the Carnival - S1-E5
Continuity mistake: When Monk is in the review board hearing, in long shots, the wastebasket by the board members' table is empty. When one of the reviewers throws away a paper that misses the basket and lands right next to it, there are several papers already in it. In the next long shot and for the rest of the scene, the basket is empty again and the missed paper is at least two feet away. (00:06:15 - 00:07:40)
Mr. Monk Goes to the Carnival - S1-E5
Plot hole: It makes no sense why the police haven't done the most obvious thing and checked for fingerprints on the murder weapon (the knife). It would not only back up the detective's claim that he did not stab the victim (he never touched the knife) but would have given the police a major clue to finding and prosecuting the murderer.
Mr. Monk Goes to the Carnival - S1-E5
Continuity mistake: When Kitty runs up to Gitomer, she is not wearing gloves. Later, when Monk gives his summation, careful viewing will show Kitty wearing a glove that's used to hold the knife.
Mr. Monk Goes to the Carnival - S1-E5
Other mistake: Kitty, the killer, is seen running to Gitomer after Lt. Kirk leaves him. She is supposedly running to stab him, but you can see that both of her hands are empty as she dashes to his side.
Mr. Monk Goes to the Asylum - S1-E6
Continuity mistake: The doctor says that Mr. Monk is allergic to tomatoes. In another episode Mr. Monk makes a sandwich with tomato. There is another episode in which Mr Monk is excited about square tomatoes.
Mr. Monk Goes to the Asylum - S1-E6
Plot hole: Monk and Manny go on the roof through Manny's window to grab a piece of cloth. Due to the possibility of suicide, it is highly unlikely that an asylum would have a window that goes directly to the roof, unlocked.
Mr. Monk Goes to the Asylum - S1-E6
Factual error: The woman who accuses Monk of stealing her necklace shouldn't have the necklace inside the asylum in the first place. For both safety and insurance reasons, patients in mental facilities aren't permitted to keep any potentially harmful jewelry, including pins, broaches, earrings, belts, beads and necklaces.
Mr. Monk Goes to the Asylum - S1-E6
Visible crew/equipment: When Monk is on the roof and helping the guy not to fall, you can see that he is tied off with a rope.
Mr. Monk and the Billionaire Mugger - S1-E7
Continuity mistake: When Sharon asks Sydney's old flame about the mugging 20 years ago, the glasses in front of them are full when they are being filmed from behind Sydney's ex, then are half empty being shown from behind Sharon, and in the next shot they are full again. (00:32:00)
Mr. Monk and the Billionaire Mugger - S1-E7
Continuity mistake: It's spring in San Francisco in this episode: warm with light rain and people outside in shirtsleeves. That is, until Monk goes to visit Kelly, when it suddenly becomes winter. Everyone's bundled in heavy coats and it's sleeting. After Monk leaves Kelly's house, it becomes spring again. [The Kelly Street sequence was originally meant to be used in "Mr. Monk and the Candidate, " where everyone is dressed appropriately for cold weather. For whatever reason, it instead got used in this episode.]
Mr. Monk and the Billionaire Mugger - S1-E7
Continuity mistake: In the opening scene, Archie Modine pulls the revolver on Sidney Teal with his right hand and fires one shot. The camera angle changes as the remaining shots are fired and Modine now has the gun in his left hand and is standing in a completely different stance. During the recap of the crime at the end of the episode, Modine fires every shot with his right hand.
Mr. Monk and the Billionaire Mugger - S1-E7
Continuity mistake: When Stottlemeyer pulls his gun on Mr. Modine, the safety is off and the gun is cocked, but in the next shot it's not cocked and the safety is on. Then we see the safety off, but not cocked.
Mr. Monk and the Other Woman - S1-E8
Plot hole: Monk says that the two files, both with tab at the middle, were kept together, which led him to discover that the person related to this file is 'the guy'. In an earlier scene, when Monk is searching the file cabinets, he picks up one of these two files and tells Sharona that this file is of 'the guy'. How can he say which one of the two files with middle tabs, which are put together, is related to 'the guy'? Impossible. (00:39:00 - 00:40:00)
Mr. Monk and the Other Woman - S1-E8
Plot hole: Monk's led to the killer because he figures out that he "added a file" to the lawyer's filing cabinet, judging by the left/middle/right tabs being off. But this makes no sense on two levels - firstly why would he need to add a file? He was just replacing the real will with a forgery. He just took the old one out and added the new one, he didn't need to mess with the filing system at all. Secondly, he picks that one out because the tabs are offset, but what if the lawyer had just taken on a new client or added other paperwork? Then the tabs would be off too, but that never seems to be considered.
Answer: Notice also that in the opening credits scene when he is touching parking meters her also wipes his hand on his clothes each time he does it.