Plot hole: The photographer who found the dead guy (Stalkerazzi) told Horatio that he was chasing a black Cadillac Escalade that was chasing the Stalkerazzi's car. He also said that he got stuck behind a truck and that when he finally caught up the Stalkerazzi was dead and there was no sign of the black Escalade. Throughout the rest of the episode nobody does any looking into the black Escalade, asks suspects if they own one or even mention it again. No investigation of the truck that the photographer got stuck behind was shown either. In the same episode Speed tells a cop, while in a tree looking into someone's yard, that they go in through windows if need be to close a case. This is totally inconsistent with the rest of the show and the law. They are always careful about getting search warrants and doing things by the book.
Revealing mistake: The compound Heptan-2-one is mentioned several times in this episode. The actress concerned persists in pronouncing the last syllable 'one' as in the number 1, whereas its correct scientific pronounciation should be as in the word 'bone' ie. sounds like 'own'. Nitpicking certainly, but a dead giveaway to any viewer with a basic knowledge of chemistry.
Other mistake: In episode "Kill Switch" it states that Jason Billings died from a broken neck, it shows Tony Decker kicking him in the face snapping his neck. Jason then tries to claw his way up onto Tony's deck leaving the scratches and blood and getting the splinter under his nail. This wouldn't have been possible since he would have already been dead.
Continuity mistake: When Horatio and Delko are on the dock talking to the blond about "Diablo" on the close up shots you can see that there is a large yacht parked at the dock she is sitting on. When the camera switches to the shots from behind looking over the pool with her at the far end, the yacht is gone.
Factual error: In the episode originally aired on 10/24/05 entitled 'Under Suspicion' Walter Dresden's DNA was positively linked to a murder in Orlando. Even if the judge dismissed the case against him in Miami, he would have been transported to Orlando to stand trial for that crime, not simply released.
Factual error: Calleigh Duquesne frequently wears completely inappropriate clothing throughout the whole series. She often wears blouses that are so low cut that the neckline is below the lower curve of her breasts. No officer of the court in the US would be allowed to dress this way. There is no grey area here, and this is not a character mistake - first time a CSI turned up at work dressed like that, she'd be sent home to change. Second time, she'd be on suspension until she agreed to change her dress standards. Also (and this regularly happens in CSI:NY as well) she is regularly wearing high heels - also a certain no-no for as CSI.
Continuity mistake: The scissors are being profiled but as seen with last scissor coming in, it's discarded after only one cut of the tape. This is NOT conclusive, as the whole blade of the scissor has to be profiled, which means he has to cut the tape at least a few times, until he has covered the whole blade, section by section
Continuity mistake: At the beginning of the episode, the bikers are approaching the crime scene to be, and you can see the sun low in the sky in the shot, casting long shadows to the right of the bikes. When they are a little closer to where the shooting will take place, suddenly it is high noon; for there are no shadows except directly underneath the motorcycles.
Continuity mistake: At the end of the broadcast as Jake and Horatio converse in front of the police station. In the closer shots, they and the motorbike are the left of the entrance steps with a car parked on the right, then in the zoom-out shots they are on the right of those steps with a cop car parked on the left.
Factual error: Every time the investigators deal with IP-addresses, the addresses on display are impossible. Each of the four parts of an IP-address has to be between 0 and 255. This isn't equivalent to the movie-specific 555 area code for phone numbers - having an IP address outside that range is like having a phone number which includes the % symbol - it's just impossible.