diff --git a/VisualStudio/osg/osg.dsp b/VisualStudio/osg/osg.dsp
index 7aea70487..5ccc1463c 100755
--- a/VisualStudio/osg/osg.dsp
+++ b/VisualStudio/osg/osg.dsp
@@ -281,10 +281,6 @@ SOURCE=..\..\src\osg\Matrixd.cpp
 # End Source File
 # Begin Source File
 
-SOURCE=..\..\src\osg\Matrix_implementation.cpp
-# End Source File
-# Begin Source File
-
 SOURCE=..\..\src\osg\MatrixTransform.cpp
 # End Source File
 # Begin Source File