Other mistake: Towards the end where they steal the chip, they are detected and about a million security guards are all running around, yet 30 seconds later, the only security guard is one man with a shotgun. What happened to their big army of security guards? (01:41:30 - 01:42:55)
Suggested correction: This isn't a mistake. Bishop had been directed to a part of the building where there weren't any security guards; this was shortly before one of the guards found their camera feed. The guy with the shotgun was the only person to head into that location. Unlikely maybe, but possible.
Continuity mistake: When Whistler is driving the van, he hits the two cars and knocks out the driver's side headlight, yet right after this and through the rest of the film, the headlight works properly. (01:51:25)
Continuity mistake: When Robert Redford tips the scrabble letters onto the glass table, he makes "SETE" and "CAST" next to it. To the right of "CAST", under his right hand, are the letters RNY, quite widely spaced. All other letters are tightly gathered above. When the angle changes to under the table, suddenly all the letters are spread fairly evenly around the table. (00:39:15)
Factual error: In the scene where Redford's character enters through the secured entrance with the stolen key-card, it shows a printer printing the time he entered. Then after his walking and getting up to the top floor and trying to get past the voice verification system and having to do it twice, they show the same printer printing the time he passed that checkpoint, and it was only one minute later than the previous time. Even though seconds are not shown, all of these actions must surely have taken longer than 1 minute and 59 seconds.
Other mistake: Wouldn't the fish have set off the motion detector?
Suggested correction: Maybe, it depends on the sensor technology. Infrared detectors, no. The fish are about the same temperature as the water. Ultrasonic detectors, no. The sound doesn't penetrate the tank. Radar detectors, no. Radar does not penetrate the water. Laser detectors, no. The beams would reflect primarily off the tank. Image analysis, maybe. The algorithm comparing the image over time might pick up the fish motion, but the discrimination would have been adjusted already to eliminate false alarms.