Continuity: The drumsticks thrown on the floor shift position.
Continuity: Nadine's necklace during the first restaurant scene.
Factual errors: The stage manager at the Ziegfeld Follies mispronounces "Ziegfeld".
Audio/visual unsynchronized: During "I Want To Go Back To Michigan", the trombone plays a muted solo, yet the trombone is open - no mute is used.
Errors made by characters (possibly deliberate errors by the filmmakers): When Hannah is explaining to Don in the rehearsal room that she can't tell left from right, she says she normally wears a garter on her left leg so she can tell which is which. She touches her left leg to indicate this.
Continuity: In the "Roof Garden" scene, Nadine is wearing high heels when she does the "Magazine Cover" number. In the wings at the end of it, she removes her headdress, discards her huge fan, and goes back onstage to call Don Hewes out of the crowd to dance their old number. Suddenly, she's wearing ballet slippers. In fact, in all of her scenes with Astaire, she wears flat shoes, so as not to tower over him.
Boom mic visible: When Hannah calls Jonathan on the phone, the shadow of the mic is very visible near a painting.
Audio/visual unsynchronized: During the "Michigan" number, 'Judy Garland' sings with a young trombone player for a whole verse. Musically, he is using a mute, but visually he is using nothing (trombone sans mute).
Miscellaneous:Robert Patrick says in his book, "Film Moi": "The most beautiful goof in movies comes in the 'Steppin' Out with My Baby' number. Fred Astaire at one point goes into slow motion. The chorus behind him continues at normal speed, but that's not the goof. 'Judy Garland', in the wings watching this miracle, just beams with admiration - as well she should."
Incorrectly regarded as goofs: In Mike's bar, a motto is shown with the possessive form of "its" spelled as "it's". While this is incorrect today, the possessive form was spelled this way before the 1900s, and thus could well have been around in 1912.
Continuity: Waiter in Mike's bar appears at the end of the bar, then when the camera changes shots, the waiter comes up to the opposite end of the bar.
Revealing mistakes: Marty is obviously not really playing the piano as is hand movements do not match the notes being played.