One may be the unit is not right, such as the disk for the metric system, and you read the file with the imperial system, or the opposite, etc.;
Two is the number of bits is not right, such as the disk for the 25 format, you read the file for 34 or 43, etc.;
Three is the way to save the wrong way to save zero, for example, the disk for the back of the save zero and you read the file for the front of the save zero, etc.;
The fourth is the more than the number of digits of the section! is based on the number of digits before or after the number of digits shall prevail;
fifth, the number of digits on the disk is too low, which leads to rounding large deviations, so the number of digits plus the decimal part can not be less than 6 digits.
The above is for reference.