diff --git a/Icarus/TopPanel/TopPanelVM.vb b/Icarus/TopPanel/TopPanelVM.vb
index 9871554..d3486bc 100644
--- a/Icarus/TopPanel/TopPanelVM.vb
+++ b/Icarus/TopPanel/TopPanelVM.vb
@@ -277,7 +277,7 @@ Public Class TopPanelVM
          m_MachiningList.Remove(MachiningIndex.Empty())
       End If
       ' se nuova lavorazione e' none
-      If SelMachining.sGUID = Guid.Empty AndAlso Not MachiningList.Any(Function(x) x.sGUID = MachiningIndex.Empty.sGUID) Then
+      If Not IsNothing(SelMachining) AndAlso SelMachining.sGUID = Guid.Empty AndAlso Not MachiningList.Any(Function(x) x.sGUID = MachiningIndex.Empty.sGUID) Then
          ' aggiungo lavorazione vuota
          MachiningList.Insert(0, MachiningIndex.Empty())
       End If