Continuity mistake: On Day 2, when the two officers go into the town's doctor's office, they leave the van with the driver's door way open, beyond 90 degrees, almost 180. The door didn't move to indicate it corrected itself as they went in. When they come out, the door is almost closed. And there has been no indication of a wind other than the helicopter, and that is supposed to be 1000 feet up and not even close to the office.
Continuity mistake: In the scene where Dutton and Hall are viewing the monitor showing where the two patients are, Dutton's symbol (initial "D" on the monitor) is shown leaving the room on the monitor. When the monitor is shown again, Dutton's and Hall's symbols are both in the room. The characters had not left the room as of yet. (00:59:15)
Factual error: There are numerous references in the film about the type of jet, a Phantom, that crashes 60 miles outside of Piedmont, with a consultant at the crash site even saying "There's no rubber at all used in a Phantom F-4, General." The crashed tail-section of the plane at the crash site is and obviously not from a Phantom jet, but from a F-84 Thunderjet, a much smaller and older jet than a Phantom.
Revealing mistake: When Dutton, Hall, and Stone are undergoing the first level of decontamination, they walk into the treatment area while completely nude. When the distorted shapes of their bodies are seen on a thermal imaging screen, you can tell that Hall is wearing briefs, even though they are supposed to have no clothing on whatsoever during the decontamination process.
Revealing mistake: During the helicopter flyover several 'corpses' are seen lying in a depression in the dust where they fell after dying (imagine a 'snow angel' to see what I mean). However, there are no footprints leading up to any of them. Any soil loose and powdery enough to form a depression when a body lands in it would hold footprints. And if there was a strong enough wind to erase footprints it would have piled some of the dust up against one or more sides of the body.
Plot hole: The sergeant tells Stone that he only has to listen for a bell for an important communication coming through and will then alert the rest of Wildfire. Yet later, Dutton notices a message already printed out. So at a facility this important, the sergeant just ignores the machine if it prints out a message and doesn't ring? He has to have clearance to read them or they wouldn't print out where he is. It's a bit too convenient for the plot that he wouldn't visually check each message to make sure.
Visible crew/equipment: When Stone and Hall are in the van in Piedmont looking for the satellite, at the point right after Stone says "hold it, you need to back up and go to the left", at two brief instances you can see the large rectangular movie light reflected in the back doors of the van. (00:21:55)
Continuity mistake: In the scene just after Dutton and Hall have their discussion in the level 5 cafeteria and are called to main control, Dutton's D symbol on the monitor turns left out of the outer room into the hallway, where main control is just to the right; but the scene continues with Dutton and Hall going in the opposite direction, walking some distance while making time for dialogue before turning right into main control, so the diagram and their movements don't match up.
Visible crew/equipment: When Stone and Hall fly over in the helicopter, the mark for the positioning of one of the 'corpses' is visible. There is a thick black line perfectly outlining the right side of the body. It's the one the camera centers on as Stone talks about the birds spreading the disease.
Continuity mistake: In the briefing room Dr. Stone is explaining Wildfire's electronic mapping system. He advises that the old man and the baby are indicated on the diagram by the two red X's. When he says this the diagram shows that the old man and the baby are at the top of the complex, just right of the elevator shaft. Dr. Hall asks to see the patients and Stone switches to a camera view. On the video it shows that the patients have instantly moved into the elevator shaft and are already descending past levels 2 and 3, not at the top of the complex as shown on the monitor.
Continuity mistake: Stone and Leavitt are examining the rock in the capsule and decide they need to send it to the lab for higher magnification. Stone uses the mechanical tweezers to remove the rock and place it in a transport chamber. After removing the rock they look at the monitor to see the patch moving (Leavitt: "My God, it's growing"). However, at this time the rock was moved and no longer under the camera. Could they have been looking at one of the patches around the rock? Not possible, the camera was moved to get the tweezers in (the last camera view was a lower magnification shot of the tweezers entering the capsule).