Index: Ringtoets/Common/src/Ringtoets.Common.IO/Structures/StructuresCharacteristicsCsvReader.cs
===================================================================
diff -u -re1cd9f27d423d4bfc6a0be647fa8388b3fefb8a2 -rac7e2e1536c9fc926fbef42cd770754cdf369cf8
--- Ringtoets/Common/src/Ringtoets.Common.IO/Structures/StructuresCharacteristicsCsvReader.cs	(.../StructuresCharacteristicsCsvReader.cs)	(revision e1cd9f27d423d4bfc6a0be647fa8388b3fefb8a2)
+++ Ringtoets/Common/src/Ringtoets.Common.IO/Structures/StructuresCharacteristicsCsvReader.cs	(.../StructuresCharacteristicsCsvReader.cs)	(revision ac7e2e1536c9fc926fbef42cd770754cdf369cf8)
@@ -281,7 +281,7 @@
             if (requiredHeaderColumnIndices.Any(i => i == uninitializedValue))
             {
                 string message = string.Format(Resources.StructuresCharacteristicsCsvReader_ValidateRequiredColumnIndices_Invalid_header_Must_have_columns_0_,
-                                               string.Join(", ", requiredHeaderColumns));
+                                               string.Join(Environment.NewLine, requiredHeaderColumns.Select(rh => "* " + rh)));
                 throw CreateCriticalFileReadException(lineNumber, message);
             }
         }