diff --git a/idaes/core/util/model_diagnostics.py b/idaes/core/util/model_diagnostics.py
index 4b5b783b56..2185ffda7c 100644
--- a/idaes/core/util/model_diagnostics.py
+++ b/idaes/core/util/model_diagnostics.py
@@ -1753,7 +1753,12 @@ def report_structural_issues(self, stream=None):
 
         # Potential evaluation errors
         # TODO: High Index?
+        if len(greybox_block_set(self._model)) != 0:
+            raise NotImplementedError(
+                "Model contains Greybox models, which are not supported by Diagnostics toolbox at the moment"
+            )
         stats = _collect_model_statistics(self._model)
+
         warnings, next_steps = self._collect_structural_warnings()
         cautions = self._collect_structural_cautions()
 
@@ -1797,6 +1802,10 @@ def report_numerical_issues(self, stream=None):
         """
         if stream is None:
             stream = sys.stdout
+        if len(greybox_block_set(self._model)) != 0:
+            raise NotImplementedError(
+                "Model contains Greybox models, which are not supported by Diagnostics toolbox at the moment"
+            )
 
         jac, nlp = get_jacobian(self._model, scaled=False)
 
diff --git a/idaes/core/util/model_statistics.py b/idaes/core/util/model_statistics.py
index 92b54fbaed..db0c6481b1 100644
--- a/idaes/core/util/model_statistics.py
+++ b/idaes/core/util/model_statistics.py
@@ -287,7 +287,7 @@ def total_constraints_set(block):
 def number_total_constraints(block):
     """
     Method to return the total number of Constraint components in a model.
-    This will include constraints provided by Greybox models using
+    This will include number of constraints provided by Greybox models using
     number_activated_greybox_equalities function.
 
     Args:
@@ -425,7 +425,7 @@ def total_equalities_set(block):
 def number_total_equalities(block):
     """
     Method to return the total number of equality Constraint components in a
-    model. This will include number of activated equalities using number_activated_greybox_equalities function.
+    model. This will include number of activated equalities Greybox using number_activated_greybox_equalities function.
 
     Args:
         block : model to be studied
@@ -571,7 +571,7 @@ def deactivated_equalities_set(block):
 def number_deactivated_equalities(block):
     """
     Method to return the number of deactivated equality Constraint components
-    in a model. This include number of deactivated equality constraints in Greybox models.
+    in a model. This will include number of deactivated equality constraints in Greybox models.
 
     Args:
         block : model to be studied
@@ -1216,7 +1216,7 @@ def unfixed_greybox_variables(block):
         block : model to be studied
 
     Returns:
-        A ComponentSet of unfixed Var components which appear in Greybox models
+        A ComponentSet of all unfixed Var components which appear in Greybox models
     """
     var_set = ComponentSet()
     for var in greybox_variables(block):
@@ -1233,8 +1233,8 @@ def greybox_variables(block):
         block : model to be studied
 
     Returns:
-        A ComponentSet including all unfixed Var components which appear within
-        activated equality Constraints in block
+        A ComponentSet of all Var components which appear within
+        activated Greybox model blocks
     """
     var_set = ComponentSet()
     for grey_box in activated_greybox_block_set(block):
@@ -1346,7 +1346,7 @@ def number_unused_variables(block):
         block : model to be studied
 
     Returns:
-        Number of Var components which do not appear within any activagted
+        Number of Var components which do not appear within any activated
         Constraints in block
     """
     return len(unused_variables_set(block))