diff --git a/toonz/sources/image/CMakeLists.txt b/toonz/sources/image/CMakeLists.txt
index d0a19c2..b610a1d 100644
--- a/toonz/sources/image/CMakeLists.txt
+++ b/toonz/sources/image/CMakeLists.txt
@@ -69,7 +69,7 @@ if(WIN32)
         mov/tiio_movW.cpp
         3gp/tiio_3gpW.cpp
     )
-else()
+elseif(APPLE)
     set(HEADERS ${HEADERS}
         mov/tiio_movM.h
         3gp/tiio_3gpM.h