diff --git a/FHEM/37_harmony.pm b/FHEM/37_harmony.pm
index 21a772f66..ef29eaa36 100644
--- a/FHEM/37_harmony.pm
+++ b/FHEM/37_harmony.pm
@@ -215,6 +215,7 @@ harmony_labelOfDevice($$;$)
 {
   my ($hash, $id, $default) = @_;
 
+  return undef if( $id eq '<unknown>' );
   return undef if( !defined($hash->{config}) );
 
   foreach my $device (@{$hash->{config}->{device}}) {