A method of prompting a failure or error, the method being applicable to a terminal apparatus comprising a fingerprint recognizer having a sensor array, characterized in that the method comprises: obtaining (21, 51, 71) electrical signals containing fingerprint information through the sensor array upon a fingerprint recognition being triggered; generating a fingerprint image according to the electrical signals containing the fingerprint information; determining (22, 53, 72) a number of sensors with abnormally-changing electrical signals in the sensor array by: for each sensor in the sensor array, determining (31, 42) an electrical signal changing value according to a current electrical signal value and an initial electrical signal value of the sensor, the current electrical signal value being a signal value detected by the sensors in the sensor array, when a user touches the sensor array; determining (32, 43) the number of sensors with electrical signal changing values exceeding a changing value threshold in the sensor array as the number of the sensors with abnormally-changing electrical signals; outputting (23. 55) prompt information upon the determined number of sensors with abnormally-changing electrical signals exceeding a number threshold; obtaining a corrected fingerprint image by removing abnormal pixels from the fingerprint image when it is determined that the number of sensors with abnormally-changing electrical signals in the sensor array does not exceed the number threshold, wherein the abnormal pixels are pixels corresponding to the number of sensors with an abnormally-changing electrical signal in the sensor array; performing the fingerprint recognition based on the corrected fingerprint image. obtaining (21, 51, 71) electrical signals containing fingerprint information through the sensor array upon a fingerprint recognition being triggered; generating a fingerprint image according to the electrical signals containing the fingerprint information; determining (22, 53, 72) a number of sensors with abnormally-changing electrical signals in the sensor array by: for each sensor in the sensor array, determining (31, 42) an electrical signal changing value according to a current electrical signal value and an initial electrical signal value of the sensor, the current electrical signal value being a signal value detected by the sensors in the sensor array, when a user touches the sensor array; determining (32, 43) the number of sensors with electrical signal changing values exceeding a changing value threshold in the sensor array as the number of the sensors with abnormally-changing electrical signals; for each sensor in the sensor array, determining (31, 42) an electrical signal changing value according to a current electrical signal value and an initial electrical signal value of the sensor, the current electrical signal value being a signal value detected by the sensors in the sensor array, when a user touches the sensor array; determining (32, 43) the number of sensors with electrical signal changing values exceeding a changing value threshold in the sensor array as the number of the sensors with abnormally-changing electrical signals; outputting (23. 55) prompt information upon the determined number of sensors with abnormally-changing electrical signals exceeding a number threshold; obtaining a corrected fingerprint image by removing abnormal pixels from the fingerprint image when it is determined that the number of sensors with abnormally-changing electrical signals in the sensor array does not exceed the number threshold, wherein the abnormal pixels are pixels corresponding to the number of sensors with an abnormally-changing electrical signal in the sensor array; performing the fingerprint recognition based on the corrected fingerprint image.