Boom mic visible: When Charles Morritz is in the hotel room, the mike is visible in the mirror.
Anachronisms: Tarot cards were not used for divination until the late 18th century (before that, they were playing cards).
Continuity: When Anna picks the Tarot cards for her reading, Cesca's amulets and bones are scattered across the table before her. In the next shot, when Cesca gathers up the remaining cards, the amulets are in a neat pile next to her arm.
Factual errors: The substance used to give the violin its color would not actually work in real life. The substance does not mix into varnish, and would quickly coagulate and oxidize to a dark brown or black color if it were actually used as the movie implies.
Anachronisms: When Anna walks out of Cesca's Kitchen she is clearly wearing shoes that are left and right oriented. However, right and left shoes were not created until much later.
Anachronisms: When we are shown the doorway of the concert hall in Oxford, there is clearly a modern electric doorbell button in the door frame.
Continuity: During the auction of the violin, Suzanne on the telephone first ordered "$270,000", then ordered "$300,000". But in the next clip of the same scene of the auction, "$300,000" was ordered by Nicholas Olsberg, and Suzanne ordered "$320,000". However, the two scenes are supposed to be the same.
Revealing mistakes: Anna and Nicolo look out a window at a nighttime crescent moon that has its lit side facing upward instead of toward the horizon. This orientation can only be seen in the daytime.
Audio/visual unsynchronized: When Frederick Pope is playing his new composition at the concert hall in Oxford, the last note continues for a couple of seconds after he takes the bow off the string.
Audio/visual unsynchronized: Most of the violin playing is off. There are few examples of anyone actually playing the notes you hear. In some scenes the fingers are moving while notes are not changing, but more often it's that the fingers are NOT moving while the notes are changing, and changing quite rapidly. Christoph Koncz (Kaspar Weiss) is one of the only actors who actually played the violin in the movie.
Continuity: When Xiang Pei first takes out the violin to play for her son, the violin is missing a G-string. Later when Xiang Pei takes the violin out to show to Chou Yuan, the violin has all four strings.