diff --git a/smt/applications/mfk.py b/smt/applications/mfk.py
index bc01a4eac..9ae03a54c 100644
--- a/smt/applications/mfk.py
+++ b/smt/applications/mfk.py
@@ -9,7 +9,7 @@
 """
 
 from copy import deepcopy
-
+import warnings
 import numpy as np
 from scipy.linalg import solve_triangular
 from scipy import linalg
@@ -983,7 +983,11 @@ def _check_param(self):
                 raise ValueError(
                     "MFKPLSK only works with a squared exponential kernel (until we prove the contrary)"
                 )
-
+        if self.options["eval_noise"] or np.max(self.options["noise0"]) > 1e-12:
+            self.options["hyper_opt"] = "Cobyla"
+            warnings.warn(
+                "TNC not available yet for noise handling. Switching to Cobyla"
+            )
         n_param = d
 
         if self.options["categorical_kernel"] is not None:
diff --git a/smt/applications/mixed_integer.py b/smt/applications/mixed_integer.py
index 29fdeb831..ab8a466f1 100644
--- a/smt/applications/mixed_integer.py
+++ b/smt/applications/mixed_integer.py
@@ -204,6 +204,11 @@ def __init__(
                 + " is not supported. Please use MixedIntegerSurrogateModel instead."
             )
         self.options["design_space"] = self._surrogate.design_space
+        if surrogate.options["hyper_opt"] == "TNC":
+            warnings.warn(
+                "TNC not available yet for mixed integer handling. Switching to Cobyla"
+            )
+
         self._surrogate.options["hyper_opt"] = "Cobyla"
 
         self._input_in_folded_space = input_in_folded_space
@@ -340,6 +345,12 @@ def build_kriging_model(self, surrogate):
         Build MixedIntegerKrigingModel from given SMT surrogate model.
         """
         surrogate.options["design_space"] = self._design_space
+
+        if surrogate.options["hyper_opt"] == "TNC":
+            warnings.warn(
+                "TNC not available yet for mixed integer handling. Switching to Cobyla"
+            )
+
         surrogate.options["hyper_opt"] = "Cobyla"
         return MixedIntegerKrigingModel(
             surrogate=surrogate,
diff --git a/smt/surrogate_models/krg_based.py b/smt/surrogate_models/krg_based.py
index d3e481986..1c63a8229 100644
--- a/smt/surrogate_models/krg_based.py
+++ b/smt/surrogate_models/krg_based.py
@@ -2102,6 +2102,11 @@ def _check_param(self):
                     "the length of theta0 (%s) should be equal to the number of dim (%s)."
                     % (len(self.options["theta0"]), d)
                 )
+        if self.options["eval_noise"] or np.max(self.options["noise0"]) > 1e-12:
+            self.options["hyper_opt"] = "Cobyla"
+            warnings.warn(
+                "TNC not available yet for noise handling. Switching to Cobyla"
+            )
 
         if self.options["use_het_noise"] and not self.options["eval_noise"]:
             if len(self.options["noise0"]) != self.nt: