diff --git a/services/univention-samba/26univention-samba.inst b/services/univention-samba/26univention-samba.inst
index d8e173c598..795704f598 100755
--- a/services/univention-samba/26univention-samba.inst
+++ b/services/univention-samba/26univention-samba.inst
@@ -101,7 +101,13 @@ configure_samba_role() {
 	else
 		case "${server_role:-}" in
 			domaincontroller_*)
-				univention-config-registry set samba/role?"domaincontroller"
+				printf "%0.s#" {1..78}
+				printf "\n"
+				echo "ERROR: Samba/NT (samba3) Domain Controller is not supported any more."
+				echo "       Please also note that the migration to Samba/AD is not supported any more after updating to UCS 4.3."
+				printf "%0.s#" {1..78}
+				printf "\n"
+				exit 1
 				;;
 			*)
 				univention-config-registry set samba/role?"memberserver"
diff --git a/test/ucs-test/tests/50_samba/10ucr_samba_role b/test/ucs-test/tests/50_samba/10ucr_samba_role
index af444a4e6f..5f023a4680 100755
--- a/test/ucs-test/tests/50_samba/10ucr_samba_role
+++ b/test/ucs-test/tests/50_samba/10ucr_samba_role
@@ -13,7 +13,7 @@
 KEY="samba/role"
 val="$(ucr get "$KEY")"
 case "$val" in
-domaincontroller) ;;
+domaincontroller) fail_test 110 "NT DCs are unsupported since UCS 4.3";;
 memberserver) ;;
 *) fail_test 110 "UCR variable $KEY='$val' does not contain value 'domaincontroller' or 'memberserver'" ;;
 esac