@@ -6158,12 +6158,32 @@ wintun_register_ring_buffer(struct tuntap *tt, const char *device_guid)

     }

     else

     {

-        msg(M_FATAL, "ERROR:  Wintun requires SYSTEM privileges and therefore "

-                     "should be used with interactive service. If you want to "

-                     "use openvpn from command line, you need to do SYSTEM "

-                     "elevation yourself (for example with psexec).");

-    }

+        if (!register_ring_buffers(tt->hand,

+                                   tt->wintun_send_ring,

+                                   tt->wintun_receive_ring,

+                                   tt->rw_handle.read,

+                                   tt->rw_handle.write))

+        {

+            switch (GetLastError())

+            {

+                case ERROR_ACCESS_DENIED:

+                    msg(M_FATAL, "ERROR:  Wintun requires SYSTEM privileges and therefore "

+                                 "should be used with interactive service. If you want to "

+                                 "use openvpn from command line, you need to do SYSTEM "

+                                 "elevation yourself (for example with psexec).");

+                    break;

+

+                case ERROR_ALREADY_INITIALIZED:

+                    msg(M_NONFATAL, "Adapter %s is already in use", device_guid);

+                    break;

+                default:

+                    msg(M_NONFATAL | M_ERRNO, "Failed to register ring buffers");

+            }

+            ret = false;

+        }

+

+    }

     return ret;

 }