diff --git a/flow360/component/simulation/validation/validation_output.py b/flow360/component/simulation/validation/validation_output.py
index 48613de3d..a9bf8dd26 100644
--- a/flow360/component/simulation/validation/validation_output.py
+++ b/flow360/component/simulation/validation/validation_output.py
@@ -115,7 +115,7 @@ def _check_output_fields_valid_given_turbulence_model(params):
         for item in output.output_fields.items:
             if isinstance(item, str) and item in invalid_output_fields[turbulence_model]:
                 raise ValueError(
-                    f"In `outputs`[{output_index}] {output.output_type}:, {item} is not a valid"
+                    f"In `outputs`[{output_index}] {output.output_type}: {item} is not a valid"
                     f" output field when using turbulence model: {turbulence_model}."
                 )
 
@@ -126,7 +126,7 @@ def _check_output_fields_valid_given_turbulence_model(params):
                     and entity.field in invalid_output_fields[turbulence_model]
                 ):
                     raise ValueError(
-                        f"In `outputs`[{output_index}] {output.output_type}:, {entity.field} is not a valid"
+                        f"In `outputs`[{output_index}] {output.output_type}: {entity.field} is not a valid"
                         f" iso field when using turbulence model: {turbulence_model}."
                     )
     return params
@@ -159,7 +159,7 @@ def _check_output_fields_valid_given_transition_model(params):
         for item in output.output_fields.items:
             if isinstance(item, str) and item in transition_output_fields:
                 raise ValueError(
-                    f"In `outputs`[{output_index}] {output.output_type}:, {item} is not a valid"
+                    f"In `outputs`[{output_index}] {output.output_type}: {item} is not a valid"
                     f" output field when transition model is not used."
                 )
     return params
diff --git a/tests/simulation/params/test_validators_output.py b/tests/simulation/params/test_validators_output.py
index 15d03e7bc..630026283 100644
--- a/tests/simulation/params/test_validators_output.py
+++ b/tests/simulation/params/test_validators_output.py
@@ -99,7 +99,7 @@ def test_turbulence_enabled_output_fields():
     with pytest.raises(
         ValueError,
         match=re.escape(
-            "In `outputs`[0] IsosurfaceOutput:, kOmega is not a valid output field when using turbulence model: None."
+            "In `outputs`[0] IsosurfaceOutput: kOmega is not a valid output field when using turbulence model: None."
         ),
     ):
         with imperial_unit_system:
@@ -117,7 +117,7 @@ def test_turbulence_enabled_output_fields():
     with pytest.raises(
         ValueError,
         match=re.escape(
-            "In `outputs`[0] IsosurfaceOutput:, nuHat is not a valid iso field when using turbulence model: kOmegaSST."
+            "In `outputs`[0] IsosurfaceOutput: nuHat is not a valid iso field when using turbulence model: kOmegaSST."
         ),
     ):
         with imperial_unit_system:
@@ -135,7 +135,7 @@ def test_turbulence_enabled_output_fields():
     with pytest.raises(
         ValueError,
         match=re.escape(
-            "In `outputs`[0] VolumeOutput:, kOmega is not a valid output field when using turbulence model: SpalartAllmaras."
+            "In `outputs`[0] VolumeOutput: kOmega is not a valid output field when using turbulence model: SpalartAllmaras."
         ),
     ):
         with imperial_unit_system:
@@ -149,7 +149,7 @@ def test_transition_model_enabled_output_fields():
     with pytest.raises(
         ValueError,
         match=re.escape(
-            "In `outputs`[0] IsosurfaceOutput:, solutionTransition is not a valid output field when transition model is not used."
+            "In `outputs`[0] IsosurfaceOutput: solutionTransition is not a valid output field when transition model is not used."
         ),
     ):
         with imperial_unit_system:
@@ -167,7 +167,7 @@ def test_transition_model_enabled_output_fields():
     with pytest.raises(
         ValueError,
         match=re.escape(
-            "In `outputs`[0] SurfaceProbeOutput:, residualTransition is not a valid output field when transition model is not used."
+            "In `outputs`[0] SurfaceProbeOutput: residualTransition is not a valid output field when transition model is not used."
         ),
     ):
         with imperial_unit_system:
@@ -186,7 +186,7 @@ def test_transition_model_enabled_output_fields():
     with pytest.raises(
         ValueError,
         match=re.escape(
-            "In `outputs`[0] VolumeOutput:, linearResidualTransition is not a valid output field when transition model is not used."
+            "In `outputs`[0] VolumeOutput: linearResidualTransition is not a valid output field when transition model is not used."
         ),
     ):
         with imperial_unit_system: