diff --git a/src/nm-device.c b/src/nm-device.c
index 9b182c4d32..ff9aab77af 100644
--- a/src/nm-device.c
+++ b/src/nm-device.c
@@ -1680,7 +1680,7 @@ dhcp6_start (NMDevice *self,
 	 */
 	err = nm_system_set_ip6_route (priv->ip_iface ? priv->ip_ifindex : priv->ifindex,
 	                               &dest, 8, NULL, 256, 0, RTPROT_BOOT, RT_TABLE_LOCAL, NULL);
-	if (err) {
+	if (err && (nl_get_errno () != EEXIST)) {
 		nm_log_err (LOGD_DEVICE | LOGD_IP6,
 		            "(%s): failed to add IPv6 multicast route: %s",
 		            priv->ip_iface ? priv->ip_iface : priv->iface, nl_geterror ());
diff --git a/src/nm-system.c b/src/nm-system.c
index e8b8fec11a..88db65964a 100644
--- a/src/nm-system.c
+++ b/src/nm-system.c
@@ -312,10 +312,10 @@ sync_addresses (const char *iface, int ifindex, int family,
 		}
 
 		err = rtnl_addr_add (nlh, addrs[i], 0);
-		if (err < 0) {
+		if (err < 0 && (nl_get_errno () != EEXIST)) {
 			nm_log_err (log_domain,
 			            "(%s): error %d returned from rtnl_addr_add():\n%s",
-						iface, err, nl_geterror ());
+			            iface, err, nl_geterror ());
 		}
 
 		rtnl_addr_put (addrs[i]);