This error often means that more than one range in the format being built has a range of missing values. This generally occurs when your ranges are character values, but you did not tell PROC FORMAT you are building a character format. You must either set the variable TYPE in the CNTLIN= data set equal to the letter 'C' or make the first character in the FMTNAME variable a '$' if you want PROC FORMAT to build a character format. If neither criteria is met, PROC FORMAT automatically assumes you are attempting to build a numeric format; therefore, the input ranges are converted to numeric values. If the input ranges are character, the conversion results in all missing values for the input ranges; thus, the error listed above is generated. If you are attempting to build a character format, be sure to set either the TYPE variable equal to 'C' or to include the '$' at the front of the FMTNAME variable value.