Index: data/data-jpa/src/main/java/org/apache/james/rrt/jpa/JPARecipientRewriteTable.java
===================================================================
--- data/data-jpa/src/main/java/org/apache/james/rrt/jpa/JPARecipientRewriteTable.java	(revision 1681259)
+++ data/data-jpa/src/main/java/org/apache/james/rrt/jpa/JPARecipientRewriteTable.java	(working copy)
@@ -217,7 +217,9 @@
             transaction.begin();
             int deleted = entityManager.createNamedQuery("deleteMapping").setParameter("user", user).setParameter("domain", domain).setParameter("targetAddress", mapping).executeUpdate();
             transaction.commit();
-
+            if (deleted < 1) {
+                throw new RecipientRewriteTableException("No such mapping");
+            }
         } catch (PersistenceException e) {
             getLogger().debug("Failed to remove mapping", e);
             if (transaction.isActive()) {