diff --git a/eeschema/sim/ngspice.cpp b/eeschema/sim/ngspice.cpp
index 31e83fa4b3..4d2c0a6f2c 100644
--- a/eeschema/sim/ngspice.cpp
+++ b/eeschema/sim/ngspice.cpp
@@ -282,8 +282,25 @@ bool NGSPICE::LoadNetlist( const string& aNetlist )
 
 bool NGSPICE::Run()
 {
-    LOCALE_IO c_locale;               // ngspice works correctly only with C locale
-    return Command( "bg_run" );     // bg_* commands execute in a separate thread
+    wxBusyCursor dummy;
+
+    LOCALE_IO c_locale;                     // ngspice works correctly only with C locale
+    bool success = Command( "bg_run" );     // bg_* commands execute in a separate thread
+
+    if( success )
+    {
+        // wait for end of simulation.
+        // calling wxYield() allows printing activity, and stopping ngspice from GUI
+        // Also note: do not user wxSafeYield, because when using it we cannot stop
+        // ngspice from the GUI
+        do
+        {
+            wxMilliSleep( 50 );
+            wxYield();
+        } while( m_ngSpice_Running() );
+    }
+
+    return success;
 }
 
 
@@ -296,7 +313,7 @@ bool NGSPICE::Stop()
 
 bool NGSPICE::IsRunning()
 {
-    LOCALE_IO c_locale;               // ngspice works correctly only with C locale
+    // No need to use C locale here
     return m_ngSpice_Running();
 }
 
diff --git a/eeschema/sim/sim_plot_frame.cpp b/eeschema/sim/sim_plot_frame.cpp
index d7e9f566f7..dd6cc22fba 100644
--- a/eeschema/sim/sim_plot_frame.cpp
+++ b/eeschema/sim/sim_plot_frame.cpp
@@ -1336,6 +1336,12 @@ void SIM_PLOT_FRAME::onSettings( wxCommandEvent& event )
 
 void SIM_PLOT_FRAME::onAddSignal( wxCommandEvent& event )
 {
+    if( IsSimulationRunning() )
+    {
+        DisplayInfoMessage( this, _( "Simulator is running. Try later" ) );
+        return;
+    }
+
     SIM_PLOT_PANEL* plotPanel = CurrentPlot();
 
     if( !plotPanel || !m_exporter || plotPanel->GetType() != m_exporter->GetSimType() )
@@ -1354,6 +1360,12 @@ void SIM_PLOT_FRAME::onProbe( wxCommandEvent& event )
     if( m_schematicFrame == NULL )
         return;
 
+    if( IsSimulationRunning() )
+    {
+        DisplayInfoMessage( this, _( "Simulator is running. Try later" ) );
+        return;
+    }
+
     m_schematicFrame->GetToolManager()->RunAction( EE_ACTIONS::simProbe );
     m_schematicFrame->Raise();
 }