Visible crew/equipment: When Horatio and Eric are talking in the CSI building corridor, notice the reflection of the overhead microphone on the left side mirror.
Character mistake: Horatio twice reads an extract from a letter threatening the life of the poisoned woman. The first time, he reads, "If you ever try to contact us again we will kill you," and the second time, "If you ever try to contact me again I will kill you." A close up of the letter shows it to read, "If you ever try to contact me again i'll (sic) kill you".
Character mistake: In the episode with the airplane murder they claim that oil is heavier than water, which isn't true under any circumstances. Oil is less dense and consequently lighter than water.
Plot hole: There is a large amount of blood found at Rachel Turner's apartment and it's determined to be Horatio's. He is subsequently arrested. Why wouldn't he be checked for a cut? To bleed that much would require a large cut and since it was only 24 hours it wouldn't have had time to heal, therefore proving that the blood although his had to be planted. That's too large an oversight by the police to just be a character mistake.
Factual error: During many of the episodes, we often see an overhead shot one of the CSI agents in the Hummer speeding down the Miami (or Los Angeles, where it is filmed) highway systems to a crime scene or what not. If you pay close attention, there is almost never any other traffic on the highways besides them. Very unlikely if not impossible, especially in Miami (or Los Angeles).
Factual error: In the scene in the lab where they notice the porn actress's wisdom teeth have not erupted yet, they show her lower jaw with the wisdom tooth just under the gum, but say it is 5 cm under the gum. I don't know about you but if my wisdom tooth was 5 centimetres under the gum, it would be hanging out the bottom of my jaw. (FYI, 5 cm is almost 2 inches.)
Other mistake: When Valera hands Ryan the results from her comparison of the nanny and the baby the results list XY (male) for the sex chromosomes instead of XX (female). (00:32:30)
High Octane - S5-E7
Other mistake: When the guy's head is cut off, his arms are up in the air next to his head. Yet his head is sliced clean off while his arms remain intact. And they would not have gone slack and fallen down after his head was cut off because they are right next to his cheeks (and the car was moving way too fast to allow for that anyway).
Deliberate mistake: In the episode "Bunk," a man goes in the house looking for his cat. When the cat releases the fumes, it jumps down, but when the man dies, the cat is nowhere to be found. The cat is not mentioned ever again in the episode either.
Continuity mistake: At the beginning the media broadcasts reports about hurricane Andrew, but later into the episode, this changes to Hurricane Anthony as the episode is titled.
Going Under - S5-E2
Factual error: When Eric and Ryan are talking about the motor oil and how the wear and tear on the engine make the motor oil unique to the bike. The oil left on the gun would not have matched the oil in the bike any longer since they were still being ridden and the engine would have still been depositing metal into the oil.
Revealing mistake: In episode "Triple Threat": at the end of the episode when the triplets are being walked out of the building all in a row after being charged with murder, they have their hands behind their backs like they are in handcuffs. When Beth turns around to look at Noah, you see Ashley in front of her with her fingers laced together and no hand cuffs, getting into the van.
Death Grip - S2-E4
Continuity mistake: When Jeff Corwin is explaining to Calleigh and Delko that the tooth they have came from a crocodile instead of an alligator, the jar in Delko's hand very quickly jumps from one hand to the other. (00:25:50)
Factual error: (Episode: Sun Block) At the beginning of the episode, all the pool patrons are watching an eclipse, the sky darkens and they watch as the moon passes in front of the sun. The process, from the moon first beginning to touch the sun's disc to total eclipse occurs in approximately one minute. It is impossible for an eclipse to happen that quickly; it would take at least an hour to complete the process shown.
Deliberate mistake: When they are trying to find out who the blogger is, they back trace to the IP address the person is using, the IP address they find starts with 310, the highest number any octet of an IP address can be is 255.
Factual error: Delko would not be able to work on the case, since he was present at the robbery and thus an eyewitness. An eyewitness who fired his gun at that. He would have been dismissed from the case.
Factual error: At the end of the episode when Caine and Delko discover a bomb in the SUV, Delko asks if they should try disarming it, to which Caine replies there isn't enough time. Caine gets in the vehicle and proceeds to drive it away with about three and a half minutes to go before the bomb detonates. We then see an arial overhead shot of Caine speeding down a freeway, during the daytime, with literally no traffic (not one car) around him. This is near impossible on even the least traveled Miami highways in the middle of the day.
Plot hole: Delko pulls over Hayden early in the episode and questions him. Later on the shooter from the spa is found dead and he has glove markings on his arm. Delko tells Calleigh to compare the markings to the gloves he took off Hayden and they are a match. But Delko pulled Hayden over hours before he killed the shooter. If Delko had the glove in custody, how could Hayden have worn it during the killing?
Other mistake: The hotel manager is charged with negligent homicide because he was using propane without the additive, but the victim was knocked unconscious. The additive wouldn't have made a difference.
