diff --git a/addDroplet.go b/addDroplet.go
index c395406..bcde8a5 100644
--- a/addDroplet.go
+++ b/addDroplet.go
@@ -308,6 +308,11 @@ func updateNetwork(d *DropletT, domcfg *libvirtxml.Domain) ([]*pb.Event, error)
 			}
 		}
 		if !found {
+			if checkUniqueMac(mac) {
+			} else {
+				log.Info("droplet", d.pb.Hostname, "duplicate mac address", mac)
+				return nil, errors.New("duplicate mac address")
+			}
 			var eth *pb.Network
 			eth = new(pb.Network)
 			eth.Mac = mac
diff --git a/main.go b/main.go
index b90ce59..f38dded 100644
--- a/main.go
+++ b/main.go
@@ -60,6 +60,10 @@ func main() {
 			// parsing the libvirt xml file failed
 			log.Info("error:", filename, err)
 			ok = false
+			log.Info("readXml() error", filename)
+			log.Info("readXml() error", err)
+			log.Info("libvirt XML will have to be fixed by hand")
+			os.Exit(-1)
 			continue
 		}
 		// see if the libvirt xml droplet is already here
@@ -68,6 +72,10 @@ func main() {
 			// some error. probably UUID mismatch or hostname duplication
 			// this has to be fixed by hand
 			ok = false
+			log.Info("findDomain() error", filename)
+			log.Info("findDomain() error", err)
+			log.Info("libvirt XML will have to be fixed by hand")
+			os.Exit(-1)
 			continue
 		}
 		if d == nil {
@@ -78,6 +86,8 @@ func main() {
 				ok = false
 				log.Info("addDomainDroplet() error", filename)
 				log.Info("addDomainDroplet() error", err)
+				log.Info("libvirt XML will have to be fixed by hand")
+				os.Exit(-1)
 			}
 		} else {
 			// this droplet is already here
diff --git a/validate.go b/validate.go
index 12370b8..2faaf38 100644
--- a/validate.go
+++ b/validate.go
@@ -21,6 +21,19 @@ import (
 	"go.wit.com/log"
 )
 
+// will make sure the mac address is unique
+func checkUniqueMac(mac string) bool {
+	for _, d := range me.cluster.Droplets {
+		for _, n := range d.Networks {
+			if n.Mac == mac {
+				log.Info("duplicate MAC", n.Mac, "in droplet", d.Hostname)
+				return false
+			}
+		}
+	}
+	return true
+}
+
 func checkDroplets(dump bool) bool {
 	// uuid map to check for duplicates
 	var umap map[string]string