diff --git a/include/AutomationEditor.h b/include/AutomationEditor.h
index df75ad759..1479ca1b9 100644
--- a/include/AutomationEditor.h
+++ b/include/AutomationEditor.h
@@ -270,7 +270,7 @@ private:
 	QColor m_vertexColor;
 	QBrush m_scaleColor;
 
-	friend class engine;
+	friend class Engine;
 
 
 signals:
diff --git a/include/Ladspa2LMMS.h b/include/Ladspa2LMMS.h
index 1e7dc4ae3..e24d0b382 100644
--- a/include/Ladspa2LMMS.h
+++ b/include/Ladspa2LMMS.h
@@ -71,7 +71,7 @@ private:
 	l_sortable_plugin_t m_analysisTools;
 	l_sortable_plugin_t m_otherPlugins;
 	
-	friend class engine;
+	friend class Engine;
 
 } ;
 
diff --git a/include/MainWindow.h b/include/MainWindow.h
index dd4b96db6..5a238ae34 100644
--- a/include/MainWindow.h
+++ b/include/MainWindow.h
@@ -171,7 +171,7 @@ private:
 	QTimer m_autoSaveTimer;
 
 
-	friend class engine;
+	friend class Engine;
 
 
 private slots:
diff --git a/include/Mixer.h b/include/Mixer.h
index e5fc2c3a4..a3e5c8463 100644
--- a/include/Mixer.h
+++ b/include/Mixer.h
@@ -462,7 +462,7 @@ private:
 
 	MixerProfiler m_profiler;
 
-	friend class engine;
+	friend class Engine;
 	friend class MixerWorkerThread;
 
 } ;