diff --git a/src/SMESHGUI/SMESHGUI_Hypotheses.cxx b/src/SMESHGUI/SMESHGUI_Hypotheses.cxx
index 11500d302..1facdfa59 100644
--- a/src/SMESHGUI/SMESHGUI_Hypotheses.cxx
+++ b/src/SMESHGUI/SMESHGUI_Hypotheses.cxx
@@ -402,6 +402,27 @@ bool SMESHGUI_GenericHypothesisCreator::getParamFromCustomWidget( StdParam&, QWi
   return false;
 }
 
+bool SMESHGUI_GenericHypothesisCreator::checkParams() const
+{
+  ListOfWidgets::const_iterator anIt = widgets().begin(), aLast = widgets().end();
+  for( ; anIt!=aLast; anIt++ )
+  {
+    if( (*anIt)->inherits( "SalomeApp_IntSpinBox" ) )
+    {
+      SalomeApp_IntSpinBox* sb = ( SalomeApp_IntSpinBox* )( *anIt );
+      if( !sb->isValid() )
+	return false;
+    }
+    else if( (*anIt)->inherits( "SalomeApp_DoubleSpinBox" ) )
+    {
+      SalomeApp_DoubleSpinBox* sb = ( SalomeApp_DoubleSpinBox* )( *anIt );
+      if( !sb->isValid() )
+	return false;
+    }
+  }
+  return true;
+}
+
 void SMESHGUI_GenericHypothesisCreator::onReject()
 {
 }
@@ -483,7 +504,10 @@ void SMESHGUI_HypothesisDlg::setCustomFrame( QFrame* f )
 void SMESHGUI_HypothesisDlg::accept()
 {
   if ( myCreator && !myCreator->checkParams() )
+  {
+    SUIT_MessageBox::critical( this, tr( "SMESH_ERROR" ), tr( "SMESH_INCORRECT_INPUT" ) );
     return;
+  }
   QtxDialog::accept();
 }
 
diff --git a/src/SMESHGUI/SMESHGUI_Hypotheses.h b/src/SMESHGUI/SMESHGUI_Hypotheses.h
index c46be7f34..043f26024 100644
--- a/src/SMESHGUI/SMESHGUI_Hypotheses.h
+++ b/src/SMESHGUI/SMESHGUI_Hypotheses.h
@@ -55,7 +55,7 @@ public:
   void                         edit( SMESH::SMESH_Hypothesis_ptr,
 				     const QString&, QWidget* );
 
-  virtual bool                 checkParams() const = 0;
+  virtual bool                 checkParams() const;
   virtual void                 onReject();
   virtual QString              helpPage() const;
 
diff --git a/src/SMESHGUI/SMESHGUI_SpinBox.cxx b/src/SMESHGUI/SMESHGUI_SpinBox.cxx
index 1c06b2ea6..11e24bbdf 100644
--- a/src/SMESHGUI/SMESHGUI_SpinBox.cxx
+++ b/src/SMESHGUI/SMESHGUI_SpinBox.cxx
@@ -115,4 +115,5 @@ void SMESHGUI_SpinBox::RangeStepAndValidator( double min,
   //                        see QtxDoubleSpinBox::mapValueToText( double v )
   setRange( min, max );
   setSingleStep( step );
+  setDefaultValue( min );
 }
diff --git a/src/SMESHGUI/SMESH_msg_en.ts b/src/SMESHGUI/SMESH_msg_en.ts
index da59f429b..e54ada5e1 100644
--- a/src/SMESHGUI/SMESH_msg_en.ts
+++ b/src/SMESHGUI/SMESH_msg_en.ts
@@ -1217,6 +1217,10 @@ Are you sure want to export to MED 2.1 ?</translation>
             <source>SMESH_ID_NODES</source>
             <translation>Id Nodes</translation>
         </message>
+        <message>
+            <source>SMESH_INCORRECT_INPUT</source>
+            <translation>Incorrect input data!</translation>
+        </message>
         <message>
             <source>SMESH_INFORMATION</source>
             <translation>Information</translation>
diff --git a/src/StdMeshersGUI/StdMeshersGUI_NbSegmentsCreator.cxx b/src/StdMeshersGUI/StdMeshersGUI_NbSegmentsCreator.cxx
index 928611d8a..397040d25 100644
--- a/src/StdMeshersGUI/StdMeshersGUI_NbSegmentsCreator.cxx
+++ b/src/StdMeshersGUI/StdMeshersGUI_NbSegmentsCreator.cxx
@@ -79,6 +79,9 @@ StdMeshersGUI_NbSegmentsCreator::~StdMeshersGUI_NbSegmentsCreator()
 
 bool StdMeshersGUI_NbSegmentsCreator::checkParams() const
 {
+  if( !SMESHGUI_GenericHypothesisCreator::checkParams() )
+    return false;
+
   NbSegmentsHypothesisData data_old, data_new;
   readParamsFromHypo( data_old );
   readParamsFromWidgets( data_new );
diff --git a/src/StdMeshersGUI/StdMeshersGUI_StdHypothesisCreator.cxx b/src/StdMeshersGUI/StdMeshersGUI_StdHypothesisCreator.cxx
index 499b9bf28..203e5f739 100644
--- a/src/StdMeshersGUI/StdMeshersGUI_StdHypothesisCreator.cxx
+++ b/src/StdMeshersGUI/StdMeshersGUI_StdHypothesisCreator.cxx
@@ -340,6 +340,9 @@ namespace {
 
 bool StdMeshersGUI_StdHypothesisCreator::checkParams() const
 {
+  if( !SMESHGUI_GenericHypothesisCreator::checkParams() )
+    return false;
+
   // check if object reference parameter is set, as it has no default value
   bool ok = true;
   if ( hypType().startsWith("ProjectionSource" ))