Index: /trunk/src/VBox/Main/GuestImpl.cpp
===================================================================
--- /trunk/src/VBox/Main/GuestImpl.cpp	(revision 30902)
+++ /trunk/src/VBox/Main/GuestImpl.cpp	(revision 30903)
@@ -1173,4 +1173,9 @@
                                   tr("The guest execution service is not ready"));
                 }
+                else if (vrc == VERR_HGCM_SERVICE_NOT_FOUND)
+                {
+                    rc = setError(VBOX_E_VM_ERROR,
+                                  tr("The guest execution service is not available"));
+                }
                 else /* HGCM call went wrong. */
                 {