diff --git a/configure/RULES_BUILD b/configure/RULES_BUILD
index a7dcacf3f..4f0d0a465 100644
--- a/configure/RULES_BUILD
+++ b/configure/RULES_BUILD
@@ -533,5 +533,7 @@ include $(CONFIG)/RULES_EXPAND
 
 include $(CONFIG)/RULES_COMMON
 
+else
+    $(warning RULES_BUILD included more than once. \
+        Use 'make show-makefiles' to work out why.)
 endif # BASE_RULES_BUILD
-#	EOF RULES_BUILD
diff --git a/configure/RULES_FILE_TYPE b/configure/RULES_FILE_TYPE
index 6f6500cf3..5936fd5e0 100644
--- a/configure/RULES_FILE_TYPE
+++ b/configure/RULES_FILE_TYPE
@@ -7,9 +7,11 @@
 # in the file LICENSE that is included with this distribution.
 #*************************************************************************
 
-# Include <top>/configure/RULES_BUILD from tops defined in RELEASE* files
+# Include <top>/configure/RULES_BUILD from tops defined in RELEASE* files,
+# excluding EPICS_BASE
 #
-RELEASE_RULES_BUILDS = $(foreach top, $(RELEASE_TOPS), \
+RELEASE_RULES_BUILDS = $(foreach top, \
+    $(filter-out EPICS_BASE, $(RELEASE_TOPS)), \
     $(wildcard $($(top))/configure/RULES_BUILD))
 ifneq ($(RELEASE_RULES_BUILDS),)
   include $(RELEASE_RULES_BUILDS)