At the beginning of the film when the building is on fire; there is a boy on the left and a girl on the right shown in the background screaming out of a window. However, in the following shot which is a closeup, they are now reversed. The girl is on the left and the boy is on the right.

When Mary Blake is singing with the Boys Choir; the orientation of the boys as well as the placement of their bibles on the railing changes from one shot to another.

When Blackie snatches the necklace from his employee; he hands it back to her with his left hand. However, in the next cut he is handing it back to her again, and this time with his right hand.

The earthquake actually occurred at 5:13 am. In the movie the timing appears to be in the late evening, not in the early morning. The prologue of the opening credits states the correct time of the earthquake: April 18, 1906 at 5:13 am but it is easy to understand any confusion since with the cinematography at the time, day for night shots were used in exterior sets and with model sets, so that the full impact of the earthquake in progress could be easily seen. Also, it took at least three days for the fire to be extinguished and with the one night shot in those sequences, it appears that the timing of events after the earthquake was much shorter than it actually was.

The song "San Francisco" is sung throughout the film, and the words Golden Gate are mentioned often. This refers to the Golden Gate Bridge. But that bridge was not built for another 30 years after the film time frame.

As Blackie walks away from a building being blown up (actually a process shot), Clark Gable's head becomes momentarily transparent.

Many set elements were quite obviously flats. This includes columns in the lyric hall, a fixture hanging over the audience in the opera hall, and many other elements.

When Blackie turns off the light in his bedroom; the room goes very dark including his image in the mirror. However, after turning on the light and then turning it off again; the room is not as dark as the previous time.

As Jack Burley walks past a piano backstage at the opera, there is a copy of "The Hollywood Reporter" propped up on the piano. This publication first appeared in 1930.

After the Earthquake, the driver of a Salvation Army wagon tells Blackie Norton that he is heading to "Daly City to get milk for the kiddies." Daly City was not incorporated until 1911. In 1906 it was called Vista Grande.

The song "Hail! Hail! The Gang's All Here!", heard during New Year's Eve, was not written until 1917.

When Blackie asks Mary the name of the song that they are dancing to; she answers, "Would You". However, that song was released in 1936 and the story takes place in 1905 and 1906.

The 'highbrow number' sung by Mary Blake while Blackie Norton entertains Jack Burley and Signor Baldini in his box early in the film, is "A Heart That's Free" by Alfred G. Robyn, composed in 1910.

When Blackie is looking at the facade of a building crumbling, the giant hand of an FX technician briefly can be seen pushing the facade away from the miniature building at the top right.