Factual error: In the scene where Noah analyses the tape, he says that the 'timecode' seems to be invalid and says that every tape has a track where you can see what device was used to record it, etc. The video technology explanation originates from the original, Ringu, with the plot of The Ring changed to make it more applicable to average Americans. But a VHS tape does not have a special track for timecode. It is possible to lay a timecode onto the tape in either an analogue form via a special audio channel, or as digital information on lines 16 and 18 of the vertical interval. But this 'timecode' is only used for professional video editing. A standard VCR, like the one they were playing the tape on, does not use this, and therefore makes Noah's explanation a minute of utter nonsense.
Factual error: The license plate on Rachel's car is not a valid Washington State license plate, while similar to the very outdated original issue plates, which would have never been issued on such a new car, they are missing tabs on the front which were mandatory on those plates and all Washington plates in 2002 when the movie was filmed.
Factual error: When Rachel and Noah end up back at Shelter Mountain Inn, Noah rips up the floor with an ax. When he tosses the cicle cutout of wood planks, there are no floor joist remnants still attached underneath them. Floor joists are necessary for support, otherwise the floor would not have even held up under the weight of a person walking under them. Also, there would be no point in nailing through the planks if there was nothing to nail into.
Factual error: In the scene where Rachel is walking in the street looking at the photos she has just collected from the photo-shop, her hands (and the rest of her body) are moving in the natural way. In the shot at the photos taken from behind her you can see the ground moving underneath her but her hands are perfectly stable suggesting she is standing on a moving platform.