diff --git a/panda/src/display/Sources.pp b/panda/src/display/Sources.pp
index b749827a9b..fd8688c6a6 100644
--- a/panda/src/display/Sources.pp
+++ b/panda/src/display/Sources.pp
@@ -41,7 +41,7 @@
     displaySearchParameters.h \
     displayInformation.h \
     subprocessWindow.h subprocessWindow.I \
-    $[if $[OSX_PLATFORM], subprocessWindowBuffer.h subprocessWindowBuffer.I subprocessWindowBuffer.cxx]
+    $[if $[OSX_PLATFORM], subprocessWindowBuffer.h subprocessWindowBuffer.I]
     
  #define INCLUDED_SOURCES  \
     standardMunger.cxx \