If the column name in a flat file source contains nonalphanumeric characters, starts with a number, or contains more than 75 characters, the synchronization task modifies the column name in the flat file target.
The synchronization task truncates column names to 75 characters. For a flat file source, the Data Preview area and the Field Expression dialog box show modified column names. For a flat file target, the synchronization task changes the column name in the flat file when it generates the file at run time.