Continuity mistake: When Sara has finished processing Melanie Grace at the slot machine, Melanie gets down from her chair and a uniformed officer can be seen helping her down. However in the next shot the officer has disappeared completely.
Revealing mistake: Willows discloses a laptop with the city's grid layout inside the welder's truck, and grabs her cell to call Grissom. Just as she presses last number, he immediately answers, without so much even a ring.
19 Down (1) - S9-E9
Factual error: Season 9, Episode 9 - 19, "Down": Towards the end of the episode they are searching along railroad tracks. A MetroLink train passes by. MetroLink serves the greater Los Angeles area, but does not serve Las Vegas.
Character mistake: When Nick and Morgan are commanding the dog to find the victim's scent (and the crime scene), they both use commands in French, e.g. venez (come), trouvez (find), allez (go), and restez (stay) - these are all formal versions of each verb. Why would they command in a formal manner?
Suggested correction: Because that's the manner in which the French train their dogs - they are ordering them to do something, not asking them.
Shock Waves - S11-E1
Character mistake: When Sarah enters the lab with the bagged microchip, she tells Greg and the other CSI that she got it from Doc Robbins, when it was Super Dave who'd found it during autopsy.
Suggested correction: Sarah is standing beside Dr. Robbins when he finds the SIM card within what's left of Officer Clark's chest cavity, during autopsy (timecode 00:19:35). Dave wasn't even near Clark, he was with the corpses of Officers Morales and Hooper.
Shock Waves - S11-E1
Revealing mistake: When the bomber is shot in front of the store, he is standing in front of a shop window. It's highly unlikely that the window wouldn't get hit and shatter. The cops fire at least a couple of dozen rounds, and magically they all hit the body, nobody misses in the heat of the moment, and no bullets exit the body from the back.
And Then There Were None - S2-E9
Factual error: Ballistics expert Bobby Dawson mispronounces the word "Koch" in the term "Heckler and Koch". He pronounces it "kotch" instead of the correct, "koch" (rhyming with lock0. A ballistics expert would know the correct way.
Continuity mistake: Season 11 - Episode 20 "Father of the Bride." As the doctor's wife is sitting talking with Nick about Vegas being the fugitive capitol of the world, watch her hands. At first they are spread far apart on the table. The shot changes and they are suddenly crossed in front of her.