Continuity mistake: When Karen is sitting at the desk, with a fistful of pencils, the pencils often change position in her hand. (00:01:40)
Continuity mistake: After Will pours himself a cup of coffee, he places the coffee jug on the sink desktop. In the next shot the jug is visible on the other worktop, beside the gas cooker. (00:35:50)
Home Court Disadvantage - S6-E3
Continuity mistake: In the overhead shot of the tennis game, it is cloudy and nobody has shadows, yet in the next closeup it's sunny and shadows are now present. (00:06:45)
Continuity mistake: After Grace cuts up the vegetable and puts it into the salad bowl, she puts the knife down on the board and walks through to the other room, and speaks with Will. When she exits back through, the knife is now positioned differently. (00:09:25 - 00:10:05)
Continuity mistake: After Jack and Karen join Will and Grace at the coffee shop table, and show them Chompers, their new dog, the blue bottle lid on the table keeps moving around between shots. (00:00:45)
Bacon & Eggs - S5-E2
Continuity mistake: When Kevin Bacon is talking to Will about the cardboard cutout, Kevin throws the cutout down and it lands flat on the floor. In later shots the cutout is now leaning up against the fireplace. Then, later, it completely vanishes.
Prison Blues - S4-E4
Continuity mistake: When Karen gives her name to the police officer at the prison, the guard behind her opens the jail cell door twice. (01:03:15)
Crouching Father, Hidden Husband - S4-E3
Continuity mistake: When Will is telling the story to Karen using the small bottles of tequila, scotch, gin and vodka, the bottles sometimes change position between shots without Will touching them. (00:46:30)
A Gay/December Romance - S6-E12
Continuity mistake: When Grace starts to threaten the Happy Noodle waiter, the position of the chopsticks in the noodle bowl on the table changes a few times, then they completely vanish when she leaves. (00:07:20)
Continuity mistake: The position of Dr. Hershberg's stethascope hanging around his neck keeps changing position, ie. how long each part hangs down over his shoulders. (00:05:10)
Continuity mistake: After Will puts on his robe because Leo walks in, Will ties the robe straps so that one strap is much longer than the other one. During his conversation with Leo though, between shots, the straps suddenly both become the same length.
Sex, Losers and Videotape - S5-E20
Continuity mistake: The water bottle vanishes from table after Will puts it down, when Mr. Stine and Karen arrive.
Boardroom and a Parked Place - S5-E6
Continuity mistake: When Will is talking to Mr. Stine in the company toilets, as Stine acts all nervous, Mr. Stine's tie knot changes position a few times during their conversation, and in some shots it is pulled up tight and sometimes more loose.
Hocus Focus - S4-E24
Continuity mistake: When Jack is stroking the rabbit that he thinks is Karen, the position of the mobile phone on the side next to him changes, and also a glass of drink appears next to him in one shot, but is gone in all others, previous and after. (00:41:05)
Tea and a Total Lack of Sympathy - S2-E10
Continuity mistake: When Grace and Jack are showing their teapot, look in the background, A few of the people keep changing places depending on the camera shot. (00:30:25)
Alley Cats - S1-E21
Continuity mistake: Grace unpacks her Scrabble board game from her bag, and puts it on the table, and puts the bag on the floor. Then her friends tell her she is too competitive, so she goes to her bedroom. As she goes, you can see that the board game on the table has now been replaced by the big red bag. (01:10:05 - 01:11:55)
Continuity mistake: When April enters the room, she puts her grey jacket and red bag on the couch. When Will leaves the room, the jacket and bag have disappeared. (01:05:55)
Visible crew/equipment: When Will walks through the door, Grace picks up a ball of paper and hits it over to him with a racket. As she does, a boom is visible above her. (01:04:10)
Crouching Father, Hidden Husband - S4-E3
Continuity mistake: When Grace says "Elliot is here with me," at the school dance, she puts her left hand onto her chest. In the next shot her arm is down by her side. (00:51:45)
Fagmalion Part Four: The Guy Who Loved Me - S5-E19
Visible crew/equipment: When the maintenance man walks over from the fireplace, towards Karen, saying "The true pride that comes..." the camera pans around the glass table, and the whole stage light and stand is reflected in it.