diff --git a/koha-tmpl/intranet-tmpl/prog/en/modules/admin/preferences/patrons.pref b/koha-tmpl/intranet-tmpl/prog/en/modules/admin/preferences/patrons.pref
index 0748dbad60..7d451ecb45 100644
--- a/koha-tmpl/intranet-tmpl/prog/en/modules/admin/preferences/patrons.pref
+++ b/koha-tmpl/intranet-tmpl/prog/en/modules/admin/preferences/patrons.pref
@@ -23,11 +23,13 @@ Patrons:
                yes: Do
                no: "Don't"
          - default the card number field on the patron addition screen to the next available card number (for example, if the largest currently used card number is 26345000012941, then this field will default to 26345000012942).
+         - "NOTE: If autoMemberNum is enabled, the system preference BorrowerMandatoryField must not contain the field cardnumber."
      -
          - "The following <a href='http://schema.koha-community.org/16_11/tables/borrowers.html' target='blank'>database columns</a> must be filled in on the patron entry screen:"
          - pref: BorrowerMandatoryField
            class: multi
          - (separate columns with |)
+         - "NOTE: If autoMemberNum is enabled, the system preference BorrowerMandatoryField must not contain the field cardnumber."
      -
          - "The following <a href='http://schema.koha-community.org/16_11/tables/borrowers.html' target='blank'>database columns</a> will not appear on the patron entry screen:"
          - pref: BorrowerUnwantedField