Index: DamEngine/trunk/src/Deltares.DamEngine.Calculators.Tests/KernelWrappers/MacroStabilityCommon/ConversionHelperTests.cs
===================================================================
diff -u -r5883 -r6082
--- DamEngine/trunk/src/Deltares.DamEngine.Calculators.Tests/KernelWrappers/MacroStabilityCommon/ConversionHelperTests.cs	(.../ConversionHelperTests.cs)	(revision 5883)
+++ DamEngine/trunk/src/Deltares.DamEngine.Calculators.Tests/KernelWrappers/MacroStabilityCommon/ConversionHelperTests.cs	(.../ConversionHelperTests.cs)	(revision 6082)
@@ -97,6 +97,23 @@
         Assert.That(result.Differences.Count, Is.EqualTo(0), "Differences found converting/reconverting Soil but this ok now if diff = 3");
     }
 
+    [Test]
+    [TestCase(1.234, 1.234)]
+    [TestCase(double.NaN, 1.000)]
+    public void GivenSuTableSoilWithoutStrengthIncreaseExponent_WhenConvertingToMacrostabilitySoil_ThenStrengthIncreaseExponentIs1(double strengthIncreaseExponent, double expectedStrengthIncreaseExponent)
+    {
+        var damSoil = new Data.Geotechnics.Soil
+        {
+            ShearStrengthModel = ShearStrengthModel.SuTable,
+            StrengthIncreaseExponent = strengthIncreaseExponent
+        };
+
+        Soil macroStabilitySoil = ConversionHelper.ConvertToMacroStabilitySoil(damSoil);
+
+        // Assert 
+        Assert.That(macroStabilitySoil.StrengthIncreaseExponent, Is.EqualTo(expectedStrengthIncreaseExponent));
+    }
+    
     #endregion
 
     [TestCase(CalculationResult.NoInput, CalculationResultType.NoInput)]
Index: DamEngine/trunk/src/Deltares.DamEngine.Calculators/KernelWrappers/MacroStabilityCommon/MacroStabilityIo/ConversionHelper.cs
===================================================================
diff -u -r5881 -r6082
--- DamEngine/trunk/src/Deltares.DamEngine.Calculators/KernelWrappers/MacroStabilityCommon/MacroStabilityIo/ConversionHelper.cs	(.../ConversionHelper.cs)	(revision 5881)
+++ DamEngine/trunk/src/Deltares.DamEngine.Calculators/KernelWrappers/MacroStabilityCommon/MacroStabilityIo/ConversionHelper.cs	(.../ConversionHelper.cs)	(revision 6082)
@@ -278,7 +278,7 @@
             Cohesion = soil.Cohesion,
             FrictionAngle = soil.FrictionAngle,
             RatioCuPc = soil.RatioCuPc,
-            StrengthIncreaseExponent = soil.StrengthIncreaseExponent,
+            StrengthIncreaseExponent = soil.ShearStrengthModel == ShearStrengthModel.SuTable && double.IsNaN(soil.StrengthIncreaseExponent) ? 1.0 : soil.StrengthIncreaseExponent, // can't be NaN in MAC kernel because used for multi-stages
             UseSoilClassification = false, // Soil type is not given so make sure it is not used.
             BondStressCurve = null, // these are not supported in DAM so set to null.
             SigmaTauTable = new List<SigmaTauTablePoint>(),