Continuity mistake: While Lucy is at Ethel's apartment nervous about leaving the baby with Ricky she's wearing v-strap pumps, then she heads back to her apartment to get her coat and bag, but when Lucy walks into her apartment she's wearing ankle strap pumps instead. (00:16:00)
Continuity mistake: In the scene where Superman comes to Little Ricky's party Little Ricky has on a birthday hat. When Superman picks him up the hat is gone; it reappears when Superman gets ready to leave.
The Ricardos Are Interviewed - S5-E7
Continuity mistake: When Ricky's new agent insults the apartment building Ricky explains that Fred and Ethel are their best friends, and we see Lucy drop the toy train onto the chair and take hold of the jack-in-the-box toy (in the crook of her left arm) with her right hand, but when it cuts to the closeup the toy train is back in Lucy's right hand and the jack-in-the-box toy is once again held in her left arm. (00:03:50)
Hollywood Anniversary - S4-E24
Continuity mistake: In season 2, "The Anniversary Present," Lucy has the 19th circled on the wall calendar, which is the date of their wedding anniversary, but in this episode when the license bureau in Greenwich, Connecticut sends Ricky a telegram with their wedding date, it's now on the 7th.
Sentimental Anniversary - S3-E15
Visible crew/equipment: When Lucy puts all the golf clubs in the bag and takes a practice swing, three tape marks are visible on the carpet near Lucy's feet and the golf bag.
Continuity mistake: When Lucy handcuffs herself to Ricky we see the style of handcuffs as they phone the locksmith, but when they're both in the bedroom their handcuffs are entirely different, then their handcuffs revert to the original style when the locksmith shows up. Additionally, when Lucy cuffs Ricky's wrist note the direction of the locking bar around Ricky's wrist, but the next morning when the locksmith is with them, the locking bar is around Ricky's wrist the opposite way, which is quite impossible. (00:06:45)
Continuity mistake: When Lucy buys back her coffee table, Ethel and Fred move it to the kitchen in the Mertz's apartment. The door to the Mertz's kitchen (with its doorknob on the right) in this episode opens the opposite way, inward towards the inside of the kitchen, and not outward in the direction of the living room, as seen in all previous and following episodes, including the very next episode. (00:17:55)
Suggested correction: The kitchen is a double hinged "saloon style" door. The door opens both ways, just like in a restaurant and most kitchens of the era. This is evident in many episodes.
Your correction is describing the Ricardo apartment, that has a kitchen with the double hinged swinging door. Rewatch the episode. This mistake is referring to the Mertz's apartment, and the door leading to their kitchen is a normal type door with a doorknob and it opens only one way. The mistake is perfectly valid.
Continuity mistake: Ethel's full name in this episode is Ethel Mae Potter; however in a earlier episode, Fred calls her Ethel Louise, and in another episode she is called Ethel Roberta.
Lucy Does a TV Commercial - S1-E30
Visible crew/equipment: In the scene where Lucy supposedly stumbles on a few minutes before hand because she is drunk from the Vitameatavegamin, you can see a sliver from her living room in the backstage area.
Revealing mistake: Look closely at the Ricardos' new Pontiac convertible. There is no glass within the windshield frame.
Plot hole: In some episodes Lucy can not sing at all. In other episodes she can sing.
Never Do Business With Friends - S2-E32
Continuity mistake: In Lucy and Ricky's apartment there are six shutters between the kitchen and living room, a set of three open to the left and three open to the right, but after the washing machine falls off the porch, when Mrs. Trumble's nephew thinks they're all crazy he runs through the back door and we see a set of four shutters on one side. Also note the round knobs are at the bottom corners, when they should be higher up at the center. (The prop shutters that we see through the doorway during the porch's "exterior" shots are identical to the seven shutters that were in apartment 4A, before the Ricardos moved downstairs). (00:22:10 - 00:24:25)
Deliberate mistake: In episode "Redecorating" Lucy wins new furniture, then in the next episode "Ricky Loses His Voice" the new furniture's delivered to the apartment, and the new couch has two normal and identical seat cushions. Starting in the next episode "Lucy is Enceinte" until the episode "Lucy Wants New Furniture", in some scenes the couch has the identical short cushions, however, in other scenes one of its seat cushions (depending on the episode, it's either left or right) is much higher than the other. For example, in "Lucy Hires a Maid" the higher seat cushion's on left side while Lucy waits for her lunch, then after Ethel urges Lucy to fire the maid the short cushion's on the left. The uneven cushions are usually seen in scenes with either Desi or another male actor, who sit on the side of the couch which has the higher seat cushion. There are even scenes where both of the seat cushions are the higher ones, such as in "Lucy's Last Birthday."
Revealing mistake: While Lucy is out on the ledge, if you look at the pipe as it runs from above the ledge to below it, the two pieces of pipe don't line up. They are off about the full diameter of the pipe. Also when the pipe pulls out, it's obvious the pipe is on a hinge at the bottom and not really attached to the lower pipe. Later, there is also no stream of water falling from above where the pipe was supposed to be connected as a drain even though it is pouring out.
Lucy Wants New Furniture - S2-E28
Continuity mistake: Lucy runs back and forth from Ricardo's and Mertz's apartment through a door in Mertz's living room that is not there in other episodes before or since.
First Stop - S4-E14
Continuity mistake: In this episode, Fred and Ethel claim that the bed they are sleeping in is just like the one they have been sleeping on for years. It is double bed with a big sag in the middle. However in an earlier episode "Vacation from Marriage" they show Lucy and Ethel in the the Mertz's bedroom and they have twin beds.
Home Movies - S3-E19
Plot hole: Toward the end of the episode, when the spliced-together movie is shown, there are several scenes from the movie Lucy, Fred and Ethel shot, often showing all three of them on screen at the same time. The problem is that no one else was there with them, yet the camera follows them as they move around the room. Who was running their camera?
Home Movies - S3-E19
Factual error: In the film Lucy and the others make, there is a long sequence of footage played forwards, then "mistakenly" repeated backwards. With the equipment and techniques they were using, this would have required not only making a complete copy of the segment, but also reversing the order of individual frames. Just feeding the film in backwards would have also flipped the image vertically. The result seen would be nearly impossible to produce accidentally.
Revealing mistake: When Lucy is cutting up the fake fur coat to scare Ricky, it is clear that the parts that she has to remove are already cut and just loosely sewn in place.
Hollywood Anniversary - S4-E24
Visible crew/equipment: After Lucy rushes out with the newspaper to tell Ethel about all the movie stars coming to the party, when Lucy returns to the suite and closes the door, we can see the arm of a crew member and a board with "DPI" (Desilu Productions Inc) on it, at the bottom right side of the screen, and a bit of equipment at the top right corner. (00:15:00)
