Index: DamClients/DamUI/trunk/src/Dam/Forms/DamPlugin.cs
===================================================================
diff -u -r4949 -r4954
--- DamClients/DamUI/trunk/src/Dam/Forms/DamPlugin.cs	(.../DamPlugin.cs)	(revision 4949)
+++ DamClients/DamUI/trunk/src/Dam/Forms/DamPlugin.cs	(.../DamPlugin.cs)	(revision 4954)
@@ -955,7 +955,7 @@
 
                 if (e.Property != null && e.Property.Equals("MaxCalculationCores"))
                 {
-                    mainForm.MaxCalculationCores = damProject.DamProjectData.MaxCalculationCores;
+                    mainForm.MaxCalculationCores = Math.Min(Environment.ProcessorCount - 1, damProject.DamProjectData.MaxCalculationCores);
                 }
             }
             else if (sender == damProject.DamProjectData.WaterBoard)