Visible crew/equipment: When Nina's just been shot, and makes it to the barn to call CTU (around 7.10am), while she's speaking on the phone there's a cameraman visible on the right hand side (DVD). (00:12:40)
Visible crew/equipment: Jack Bauer and his boss are in a building at night with a shooter hidden somewhere. They open a door and look very carefully to the right and then to the left before going through the door. On the right side you can briefly see two crew members and as the camera pulls forward they back up some so they won't be seen. (00:23:50)
Visible crew/equipment: When Jack, Kim and Teri are at the compound, Kim stands up shortly before Gaines' first shot. On the left you see a crew member kneeling. (00:26:20)
Ronnie Bischof
11:00 P.M.-12:00 Midnight - S1-E24
Visible crew/equipment: At around 11:30pm, just when Jack is preparing to take his first shots at the Drazens as they are running towards the speedboat, you can see a cameraman/technician (wearing a face shield), and a TV monitor behind Jack's head.
Visible crew/equipment: When the guard surprises Rick and Kimberly in the shed, you can see an arm and parts of the camera at the left side right behind Rick when the guard leaves. (Widescreen DVD). (00:23:20)
Bjoern_Buller
Continuity mistake: In Episode 15 (Day 1), the pregnancy test that Teri takes to the bathroom is a "TrueBlue" (close up shot on it), but the one that Kim finds there is a "ClearBlue". (00:13:07 - 00:19:57)
Day 7: 4:00 PM - 5:00 PM - S7-E9
Revealing mistake: When Renee says she couldn't get the laptop to boot up due to a fried hard drive, the Windows desktop is visible on it, which meant that the laptop did boot up.
Continuity mistake: In the police station, Kim's right arm is handcuffed to the bench as we see the profile/ master shot of her and Rick, but in the next shot, (the medium/front), Kim's right arm is behind her now and not cuffed, as Rick is being cuffed to the bench. A few seconds later, her right arm is again handcuffed to the bench. Kim's right arm is moving around as she talks to Rick and the scene progresses. Her left arm is finally uncuffed when the detective goes to book her. (00:06:20)
Day 3: 11:00 P.M.-12:00 A.M. - S3-E11
Trivia: When the CTU personnel are in a meeting and Adam brings a picture of Nina onto the big screen, the name next to the picture is Sarah Berkeley, which is Sarah Clarke's married name. Clarke has been married to Xander Berkeley since 2002.
Day 6: 6:00 AM - 7:00 AM - S6-E1
Trivia: Stephen Merchant, co-creator of "The Office" (original UK version) makes a cameo as a CTU worker who Nadia Yassir hands a document to. Merchant's co-creator/star, Ricky Gervais, also filmed a cameo as a presidential aide, but was eventually cut; Gervais' cameo is located in the deleted scenes on the DVD box set. (00:07:05)
Cubs Fan
Factual error: At about 5:45pm, Teddy is viewing Jack through his rifle scope, but there are no cross hairs, nor any other reticles. (00:31:20)
Continuity mistake: In the 08:00 - 09:00 episode on DVD (and during the previous few hours) you see Kim Bauer's feet and she is wearing sandals with no socks. At 08:36 when Terri has just been taken from the room where they are being held captive you see a shot of Kim sitting down and you can see that she is wearing pink leather slipper style shoes and black socks.
11:00 A.M.-12:00 Noon - S1-E12
Visible crew/equipment: When Alberta is in holding room 2 with Tony, there is a camera visible to the left of the screen, behind Alberta. You can see it three times during their conversation. (00:21:50)
darren-c
Day 7: 4:00 PM - 5:00 PM - S7-E9
Other mistake: When Morris drops Chloe off at the FBI, he asks if she's sure she doesn't need his help. In the subtitles, Morris' name is incorrectly displayed as "Miles".
Cubs Fan
12:00 Midnight-1:00 A.M. - S1-E1
Continuity mistake: When Kim is sitting on the roof of the furniture store she is looking straight ahead. However the camera changes and now she is looking down. (00:18:05)
Ssiscool
12:00 Midnight-1:00 A.M. - S1-E1
Continuity mistake: Janet jumps up on a table at the furniture store and is joined by a bloke who proceeds to have a drink from a can of beer. The camera does a quick cut and the drinker's position has completely changed. (00:12:30)
Ssiscool 
12:00 Midnight-1:00 A.M. - S1-E1
Visible crew/equipment: When Rick leads Kim into the store, as the door closes so a large white stage light or light screen is reflected in the door. (00:12:05)
Ssiscool 
12:00 Midnight-1:00 A.M. - S1-E1
Visible crew/equipment: When Jack drives off in his car to go to CTU, as the car drives off a stage light is reflected in the cars paintwork. (00:08:05)
Ssiscool 
12:00 Midnight-1:00 A.M. - S1-E1
Visible crew/equipment: When Terri stands up to go and talk to Kim with Jack at the start the camera pans too far to the left and part of the filming equipment is visible in the shot. (00:05:35)
Ssiscool 
12:00 Midnight-1:00 A.M. - S1-E1
Continuity mistake: When we first see Jack he has his hand up by his mouth and then by his chest. When the camera changes to show Kim, his hand is now lowered. (00:03:30)
Ssiscool 
Answer: This is unintentional and a simple continuity mistake.
Ssiscool