diff --git a/lib/Slic3r/GUI.pm b/lib/Slic3r/GUI.pm
index dca7bb6f4..7b82de30b 100644
--- a/lib/Slic3r/GUI.pm
+++ b/lib/Slic3r/GUI.pm
@@ -325,9 +325,13 @@ sub scan_serial_ports {
         # Windows
         if (eval "use Win32::TieRegistry; 1") {
             my $ts = Win32::TieRegistry->new("HKEY_LOCAL_MACHINE\\HARDWARE\\DEVICEMAP\\SERIALCOMM",
-                { Access => Win32::TieRegistry::KEY_READ() });
-            $ts->Tie(\my %reg);
-            push @ports, sort values %reg;
+                { Access => 'KEY_READ' });
+            if ($ts) {
+                # when no serial ports are available, the registry key doesn't exist and 
+                # TieRegistry->new returns undef
+                $ts->Tie(\my %reg);
+                push @ports, sort values %reg;
+            }
         }
     } else {
         # UNIX and OS X