The One With Ross's Inappropriate Song - S9-E7
Visible crew/equipment: When Monica comes home at the end, as Joey pulls her down on top of Chandler as to protect her eyes from seeing the tape, you can see a knee pad on Courteney Cox's knee, under her skirt. (00:14:20)
The One With The Mugging - S9-E15
Continuity mistake: When Phoebe and Ross are 'mugged' it is dark and in the evening. However, when Ross tells Monica what had 'just' happens you can see that it is the middle of the day. (00:07:45)
The One Where Emma Cries - S9-E2
Continuity mistake: When Rachel wakes up Emma during a nap, against Phoebe's advice, there is a shot of Emma in the cot. She is wearing a plain pink hat, but in the next shot, when Rachel lifts her out of the cot, she is wearing a white hat with what looks like little flowers on it. (00:05:55)
The One With The Blind Dates - S9-E14
Continuity mistake: When Phoebe says that they should not tell Ross that the date is cancelled so that he gets stood up, Joey says, "I hear that's bad" - implying that he has never been stood up so doesn't know how it feels. However, in TOW Two Parts (Part II), Ursula stands Joey up, and he takes it pretty bad. (00:06:40)
The One With The Lottery - S9-E18
Continuity mistake: In TOW the lottery tickets series 9 just after Chandler has got the job and he sits down you can see Joey's hand in the right side of the screen however when the shot changes Joey moves his hands up to the position we have just seen. The shot changes back and his hand is in the same position. (00:18:50)
The One With The Fertility Test - S9-E21
Visible crew/equipment: When Monica and Chandler are on the couch in the fertility clinic after Monica says "Nobody's gonna wanna watch that" the camera switches to a wider shot. When it does this the boom mic swiftly moves out of view. (00:12:20)
The One With Rachel's Dream - S9-E19
Visible crew/equipment: After Monica and Phoebe apologize to each other at Javu, when it cuts to Rachel walking into the apartment we can see part of the hole in the wall beside the bulletin board, and the light fixture above it is gone.
The One With Rachel's Other Sister - S9-E8
Continuity mistake: When Rachel tells Amy that she'll let her use the Ralph Lauren discount Amy hugs her, and the glass Amy's holding in her left hand switches to her right hand and then back to her left hand, between shots.
The One With Rachel's Other Sister - S9-E8
Continuity mistake: When Ross, Rachel, and Amy arrive at Monica and Chandler's apartment the table is set, and there are folded napkins in napkin rings on the plates at each place setting, but after Amy insults Joey all the napkins have vanished.
The One With the Male Nanny - S9-E6
Continuity mistake: When Mike and Phoebe are at Central Perk, Mike pulls his apartment key out of his pocket and he's holding the head of the key with the shank side up, but next shot he's holding the shank with the head side up.
The One With the Sharks - S9-E4
Continuity mistake: After Monica, Rachel, and Joey have been discussing Joey's problem Monica asks him if he thinks sharks are sexy, and when Joey asks about the Little Mermaid it cuts to Monica's closeup and the water bottle cap is on, but in the next closeup of Rachel the cap is off.
The One Where No One Proposes - S9-E1
Revealing mistake: While everyone's looking at Emma through the window, when Jack makes the comment about the first grandchild, someone in the background walks by and causes the hallway's set wall to wobble behind them.
The One In Barbados, part 1 - S9-E23
Revealing mistake: On a number of occasions in this and the next episode, the beach and the water can be seen in the background, through hotel windows. White foam is visible in a number of places, like the crests of waves, but not only do they not move while the camera is on them, they are always in the same place in subsequent shots, revealing that this is a painted backdrop. (00:26:40)
The One With the Male Nanny - S9-E6
Continuity mistake: Towards the end, during a scene at Ross and Rachel's, Sandy picks up two puppets and puts them on each hand. He starts pulling the blue one onto his left hand, but when the angle changes there's a yellow one on his left hand, and a blue one on his right. It cuts to Ross, then when we go back to Sandy they've changed hands again. (00:24:30)
The One In Barbados, part 2 - S9-E24
Continuity mistake: In the final episode of series 9 part 2 where Phoebe is talking to first David and then Mike the shot keeps changing. Each time it does the amount of hair down Phoebe's back changes from a little to a lot. (00:23:30)
The One With Phoebe's Rats - S9-E12
Continuity mistake: In the one with Phoebe's rat babies, it is very obvious that the box has nothing in it. Also when she is in her apartment explaining about giving up the triplets she had for her brother she puts the box down on the table, yet when it cuts to Mike's face and Phoebe's realisation that she hadn't told him that before, the box is back on her lap. (00:14:05)
The One Where No One Proposes - S9-E1
Continuity mistake: In the scene where Rachel believes Joey has proposed to her at the hospital after having Emma. Ross is talking to Rachel about her saying yes to Joey's proposal. The nurse brings Emma in to breast feed. When the nurse leaves, she closes the door. However, when they shoot back to Joey a couple of times before he leaves the room, the door is open. (00:19:45)
The One In Barbados, part 2 - S9-E24
Character mistake: When Monica and Mike are playing table tennis, Monica puts her hand on the table and looses the point. Mike then does the same thing. Surely Monica, of all people would notice that as it would have given her the point. We also see her looking at Mike at the time. (00:33:40 - 00:39:25)
Suggested correction: Not really a mistake to not notice it, especially when it may be what a character like Monica would notice. She is being extremely competitive and frustrated because Mike just denied her a point, so it's fair to say human nature plays a part here.
The One In Barbados, part 2 - S9-E24
Continuity mistake: In the One in Barbados (part 2), just after Monica bashes her hand against the table, the shot of Chandler asking if she's OK shows Monica raising a finger right at the edge of the screen. We then cut to Monica, who's cradling both her hands together. (00:42:50)
The One With The Lottery - S9-E18
Continuity mistake: In The One With The Lottery, Chandler is on the phone to find out if he got the job, he then hangs up and rolls up one of his sleeves. In the next shot of him both sleeves are rolled up. Then you can see his sleeves slip down again, but when it cuts to a closer shot, you can see they're rolled up again. (00:04:40)