Index: Ringtoets/AssemblyTool/src/Ringtoets.AssemblyTool.IO/Model/SerializableAssessmentProcess.cs
===================================================================
diff -u -r1a21fe49fb4da6afcf09e90eb99c40cdcabf46df -ra30b67748bed77736f62b6b3c30c82649bb9cf4e
--- Ringtoets/AssemblyTool/src/Ringtoets.AssemblyTool.IO/Model/SerializableAssessmentProcess.cs	(.../SerializableAssessmentProcess.cs)	(revision 1a21fe49fb4da6afcf09e90eb99c40cdcabf46df)
+++ Ringtoets/AssemblyTool/src/Ringtoets.AssemblyTool.IO/Model/SerializableAssessmentProcess.cs	(.../SerializableAssessmentProcess.cs)	(revision a30b67748bed77736f62b6b3c30c82649bb9cf4e)
@@ -44,14 +44,14 @@
         /// </summary>
         /// <param name="id">The unique ID of the assessment process.</param>
         /// <param name="assessmentSection">The assessment section this process belongs to.</param>
-        /// <exception cref="ArgumentNullException">Thrown when <paramref name="id"/>
-        /// or <paramref name="assessmentSection"/> is <c>null</c>.</exception>
+        /// <exception cref="ArgumentException">Thrown when <paramref name="id"/> is <c>null</c> or empty.</exception>
+        /// <exception cref="ArgumentNullException">Thrown when <paramref name="assessmentSection"/> is <c>null</c>.</exception>
         public SerializableAssessmentProcess(string id,
                                              SerializableAssessmentSection assessmentSection) : this()
         {
-            if (id == null)
+            if (string.IsNullOrEmpty(id))
             {
-                throw new ArgumentNullException(nameof(id));
+                throw new ArgumentException($@"'{nameof(id)}' must have a value.");
             }
 
             if (assessmentSection == null)