Goofs

When Gin is stealing the mask, she carefully raises her leg to avoid a laser, and then moves both arms right through the same beam.

Gin's shoes in the final running/climbing sequence around the bridge and the building repeatedly change from very high heels to flats.

After a brief car chase Mac pulls up to the curb and we see the car is heavily damaged on all sides; the damage is much more extensive than this chase caused. On the DVD there is a deleted scene of a much longer car chase that explains this discrepancy.

After Gin loses her mini-parachute she can be seen wearing it when standing on the bridge between the towers before Mac has given her his parachute.

When navigating through the red strings with a blindfold, Virginia gently nudges a string with her leg and it shakes, but she is said to have passed the test afterwards.

At the training Robert MacDougal says that 5db is too loud for the explosions. But 5db is about the same as a person breathing. They talk louder then that when they are counting.

Infrared lasers are not visible through thermal imaging

Gin tells Hector that for stealing the mask Mac will get 20 years to life for grand larceny, the crime takes place in the UK where such a crime would be non-dwelling burglary and subject to a maximum sentence of 10 years.

PIR detectors cannot be "blinded" with visible range laser (the sensor element detects IR, not visible range), and even if they tried to use IR laser they would only set off an alarm.

The tour guide at the Petronas Towers says they are 700 feet in the air when they are on the bridge. Malaysia is on the metric system so he most likely would have given the height in meters.

In the train scene, Hector points his gun at Gin with his finger all the way inside the trigger guard, but behind the trigger, a position from which it would be impossible to fire. He has no intention of firing, and in fact would want to take no chance.

When Gin is stealing the mask, she uses powder to reveal on last laser beam that Mac can't she because she is blocking it. However, if she had actually blown on her powder hard enough to get enough powder off to see the beam, she would have set off the alarms. This would be the case if it would have been normal foundation, however there is no consensus to the fact as it could have been a much lighter, and, therefore, not as likely to set off the alarms powder.

When stealing the mask it takes Gin about two minutes to pass through the laser grid. When she takes the mask, Mac tells her there are about 30 seconds left before the guard reaches the room. When the guard finally reaches the door Gin has already vanished, but the laser grid is still active. Given that, it becomes easy to explain that, in getting to the mask, she would have been slow and careful, but not necessarily so when she retrieved it. Also, with the practice undertaken, it would make sense that, in real time, it would probably take her about 30 seconds or so to get through it, and just appeared to be longer to increase the dramatic tension.

The Malaysian UTK personnel use a small explosive charge to blow open the hatch. However, they just bend down as it explodes and that will still injure them. No police tactical team would make such a mistake.

Sean Connery's character is referred to as 'Mac' throughout the film, short for MacDougal. On the Waverly Insurance database on Gin's computer, visible on the blu ray release as she scrolls through his file, it states that Mac was, "born in Edinburgh, Scotland, and named for its Saint". (Connery was indeed famously born in Edinburgh.) The patron Saint of Edinburgh is St. Giles - making him 'Giles MacDougal'. Although his first name is never spoken in the film, he is referred to as 'Robert MacDougal' in the film's marketing material. No explanation is given for this inconsistency, which is likely an oversight by the art department.

When we first see our heroes' watches being synchronized, they actually are off by one second.

After visiting the exhibit the protagonists drive away. The gates close with a sound effect that is wrong. It reverberates like it happens in a closed environment instead of in the open.

Gin's voice isn't matching her lip movements, in the scene when she's walking on the beam.

The Petronas Towers in Malaysia are not located immediately beside slums. The scenes involving the hideout in Malaysia were filmed in actual slums, and the towers were added into the film later. The Malaysian government complained about this as they felt it misrepresented their rich/poor divide.

Kuala Lumpur is not in the Southern Hemisphere - it is actually a little over three degrees north of the equator. Being that close to the equator, it is always "summer", and the days and nights are very close to equal length all year 'round.

When Gin is swimming in the bay outside the castle, it is supposedly 1 week before Christmas. Absent any local hot springs, that water in Scotland on 18 December might have been 40 degrees F on a good day.

Also note all the green grass surrounding the castle.

Gin uses chewed gum to neutralize the pressure switch while stealing the mask. This would leave her DNA behind. Some would argue that she was setting up Mac and would not care, but she was unaware that Mac knew who she was at that time. Her leaving DNA would mark her as careless and tip him off.

Gin tells Mac that the heist is to be pulled "tomorrow night," yet the day they conduct the heist is one day after that.

At 11:00 PM on the night of the Millenium Heist, Gin says they will now gain one tenth of a second every minute until midnight to gain the extra ten seconds the heist requires. However, 60 minutes' worth of gains will only yield them six extra seconds.

When stealing the mask, Mac says there are "75 seconds" until the guard shows up. That time has long since passed as he says "35 seconds". That 35 seconds also passes LONG before the guard opens the door and sees the "Monkey". Apparently Mac can't read a second hand. Additionally, for Gin to place the monkey and escape that quickly without setting off the alarm is impossible, she would have had to complete her exit before the guard turned off the alarm and opened the door, to avoid being seen by him.

Catherine is wearing her wedding rings in one short scene when practicing with the red strings.

When Virginia is explaining to her boss the break-in to steal the Rembrandt painting, she quotes Mao Zedong (or Chairman Mao) as saying, "Let a thousand flowers bloom." The actual quote from Mao was to "let a hundred flowers bloom" referring to the Hundred Flowers Movement which preceded the Cultural Revolution in China.