diff --git a/core/api/src/main/java/org/onosproject/store/service/DocumentPath.java b/core/api/src/main/java/org/onosproject/store/service/DocumentPath.java
index 333cbb1..0ef9aef 100644
--- a/core/api/src/main/java/org/onosproject/store/service/DocumentPath.java
+++ b/core/api/src/main/java/org/onosproject/store/service/DocumentPath.java
@@ -74,8 +74,8 @@
     public DocumentPath(String nodeName, DocumentPath parentPath) {
         checkNotNull(nodeName, "Node name cannot be null");
         if (nodeName.contains(pathSeparator)) {
-            throw new IllegalDocumentNameException(
-                    "Periods are not allowed in names.");
+            throw new IllegalDocumentNameException("'" + pathSeparator + "'" +
+                    " are not allowed in names.");
         }
         if (parentPath != null) {
             pathElements.addAll(parentPath.pathElements());