Continuity mistake: The amount of frothy foam on top of the protein shake differs through consecutive shots, as Grace is about to drink it, and after she has taken a sip and as Will and she talk in the kitchen area. (00:20:55)
Boo! Humbug - S1-E5
Continuity mistake: When Will and Grace are taking the kids around the flats trick or treating, as Will and Grace enter the lift, the kids stand in the hall and their pumpkin bags have faces, but in the next shot they are plain orange. (00:56:05)
Big Brother is Coming (1) - S1-E14
Continuity mistake: When Will is throwing ties from the closet, we see that they all land on the floor. The angle changes, and one has now appeared on the bed. (00:08:50)
Continuity mistake: When Grace is putting on the waterworks in front of the landlord, to get a lower cut on the apartment, the bowl of tassels on the table is repeatedly full/half full, and tassels jump in and out of the bowl. (00:16:00)
Alley Cats - S1-E21
Continuity mistake: When Rob & Ellen are confronting Grace about how competitive she is, there are several shots of them from the same angle. In some shots there is a red bag visible in the bottom left corner, in others it disappears.
Will on Ice - S1-E11
Continuity mistake: When Karen arrives at work, she places her bags on the chair, and then puts them down onto the floor. In a following shot they are back on the chair, then in another shot they're gone again. (00:07:55)
Continuity mistake: When Karen enters the apartment, the position of the board game boxes on the table change, especially the long white board game box which just out and back into a stack. (00:55:05)
Will on Ice - S1-E11
Continuity mistake: When Will and Grace stand in the kitchen discussing the grey hair, the back of cereal packet (on the counter) faces the camera, but for one shot the front of the packet is showing. (00:00:35)
Big Brother is Coming (1) - S1-E14
Continuity mistake: When Will tosses all the ties out of his cupboard, the tie which landed on the end of his bed keeps changing. In some shots it's a blue and black stripy tie, in others it's a yellow and brown stripy tie. (00:08:50)
Where There's a Will There's No Way - S1-E7
Visible crew/equipment: When Karen enters the office with clothes and bags, Grace says "Oh Karen, you didn't have to buy me clothes," and above her is the whole boom dipping into view. (01:05:40)
Boo! Humbug - S1-E5
Continuity mistake: When the father comes to pick up his children, the plastic pumpkin goody-bag moves from the edge to the centre of the rug between shots. (01:01:00)
Big Brother is Coming (2) - S1-E15
Continuity mistake: Several parts of the mess in Will's apartment keep switching places. Look at the glasses and napkins. (00:20:45)
Alley Cats - S1-E21
Revealing mistake: When Will goes to pour himself a glass of whiskey, the brown liquid that is chosen to represent the liquor has foam bubbles on the top of it that resemble the ones that soda has.
Continuity mistake: When we first see Grace in her apartment with everything in place, there is a peach coloured chair with a red sheet thrown over it, which changes position in the next shot. (00:39:10)
Where There's a Will There's No Way - S1-E7
Continuity mistake: The bites in Graces chocolate donut change. (01:05:35)
Continuity mistake: When Will is standing cleaning a tray, on the counter behind him there is a large circular wooden board, with a white tea-towel sitting on it. After he cleans the tray and walks off, the white tea-towel has moved off the wooden board, and is on the edge of the counter. (00:09:55)
Continuity mistake: When Karen is lying on the table, her jacket is unbuttoned. And when Jack pushes her off the table and she gets back up, it's still unbuttoned. But as the shot cuts to her heading quickly over to the door, her jacket is now buttoned, but there was no time for her to do it.
Continuity mistake: When Grace has the idea to move into Will's apartment, we can see her cup of coffee on the table. Then a little later during their conversation, the cup moves. (00:23:00)
Continuity mistake: After Grace tells Will he has to go on a second date with Nathan, she runs out onto the terrace to hide. When she comes back into the kitchen, she leaves the terrace door open. In the next shot it's closed, the open again. (00:16:40)