diff --git a/RhSolutions.AddIn/Services/GuessReader.cs b/RhSolutions.AddIn/Services/GuessReader.cs
index 6a2acb6..52e53b6 100644
--- a/RhSolutions.AddIn/Services/GuessReader.cs
+++ b/RhSolutions.AddIn/Services/GuessReader.cs
@@ -57,6 +57,11 @@ public class GuessReader : IReader
         int successCounter = 0;
         object[,] cells = column.Value2;
 
+        if (cells == null)
+        {
+            return false;
+        }
+
         for (int row = 1; row < column.Rows.Count + 1; row++)
         {
             object currentCell = cells[row, 1];
@@ -81,9 +86,15 @@ public class GuessReader : IReader
 
     private bool IsAmountColumn(Range column, out double average)
     {
-        object[,] cells = column.Value2;
-        int successCounter = 0;
         average = 0.0;
+        object[,] cells = column.Value2;
+
+        if (cells == null)
+        {
+            return false;
+        }
+
+        int successCounter = 0;
 
         for (int row = 1; row < column.Rows.Count + 1; row++)
         {