diff --git a/src/osgViewer/PixelBufferCarbon.cpp b/src/osgViewer/PixelBufferCarbon.cpp
index 1bed7b526..b2f7c2684 100644
--- a/src/osgViewer/PixelBufferCarbon.cpp
+++ b/src/osgViewer/PixelBufferCarbon.cpp
@@ -7,7 +7,7 @@
  *
  */
  
- #ifdef __APPLE__
+#if defined (__APPLE__) && (!__LP64__)
 
 #include <osg/observer_ptr>
 #include <osgViewer/api/Carbon/PixelBufferCarbon>
@@ -168,4 +168,4 @@ PixelBufferCarbon::~PixelBufferCarbon()
 
 
 
-#endif
\ No newline at end of file
+#endif