diff --git a/voltha/northbound/openflow/Makefile b/voltha/northbound/openflow/Makefile
index 0073d1e..e0854b1 100644
--- a/voltha/northbound/openflow/Makefile
+++ b/voltha/northbound/openflow/Makefile
@@ -14,7 +14,9 @@
 # limitations under the License.
 #
 
-VOLTHA_BASE:=../../../.
+ifeq ($(VOLTHA_BASE)_set,_set)
+$(error If your getting this error, please type ". ./env.sh" at the top directory)
+endif
 
 include $(VOLTHA_BASE)/setup.mk