diff --git a/tuntap_osx.c b/tuntap_osx.c
index ee06ef8..e746769 100644
--- a/tuntap_osx.c
+++ b/tuntap_osx.c
@@ -46,7 +46,8 @@ int tuntap_open(tuntap_dev *device /* ignored */,
   }
   
   if(device->fd < 0) {
-    traceEvent(TRACE_ERROR, "Unable to open tap device");
+    traceEvent(TRACE_ERROR, "Unable to open tap device %s", tap_device);
+    traceEvent(TRACE_ERROR, "Please read https://github.com/ntop/n2n/blob/dev/doc/n2n_on_MacOS.txt");
     return(-1);
   } else {
     char buf[256];