I have my city, state and ZIP code all in one field, however when I
presort my list it tells me “ZIP code is not defined?
In order to run your list through the presort function of MAILERS+4
you must have a separate ZIP code field formatted in your list. When
using a .DBF file, go to the “Modify” function under the “Database”
menu. Insert a ZIP code field with a length of 10 and then format
the field as “ZIP” in format fields.