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.
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.Christoph Galuschka
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).