diff --git a/apis/openstack-nova/src/main/java/org/jclouds/openstack/nova/v2_0/compute/functions/NovaSecurityGroupInRegionToSecurityGroup.java b/apis/openstack-nova/src/main/java/org/jclouds/openstack/nova/v2_0/compute/functions/NovaSecurityGroupInRegionToSecurityGroup.java
index 184e9ab4b1..f39da8faf1 100644
--- a/apis/openstack-nova/src/main/java/org/jclouds/openstack/nova/v2_0/compute/functions/NovaSecurityGroupInRegionToSecurityGroup.java
+++ b/apis/openstack-nova/src/main/java/org/jclouds/openstack/nova/v2_0/compute/functions/NovaSecurityGroupInRegionToSecurityGroup.java
@@ -103,7 +103,7 @@ public class NovaSecurityGroupInRegionToSecurityGroup implements Function<Securi
            final Collection<org.jclouds.openstack.nova.v2_0.domain.SecurityGroup> referredGroup =
               groupInRegion.getGroupsByName().get(ruleGroup);
            if (null == referredGroup) {
-              logger.warn("Unknown group {} used in security rule, refusing to add it to {} ({})",
+              logger.warn("Unknown group %s used in security rule, refusing to add it to %s (%s)",
                  ruleGroup, owningGroup.getName(), owningGroup.getId());
               return null;
            }