diff --git a/reactos/cmake/msvc.cmake b/reactos/cmake/msvc.cmake
index 6c1dd2207b8..abed8f8af47 100644
--- a/reactos/cmake/msvc.cmake
+++ b/reactos/cmake/msvc.cmake
@@ -153,6 +153,7 @@ function(spec2def _dllname _spec_file)
         OUTPUT ${CMAKE_CURRENT_BINARY_DIR}/${_file}.def ${CMAKE_CURRENT_BINARY_DIR}/${_file}_stubs.c
         COMMAND native-spec2def --ms --kill-at -a=${SPEC2DEF_ARCH} -n=${_dllname} -d=${CMAKE_CURRENT_BINARY_DIR}/${_file}.def -s=${CMAKE_CURRENT_BINARY_DIR}/${_file}_stubs.c ${CMAKE_CURRENT_SOURCE_DIR}/${_spec_file}
         DEPENDS ${CMAKE_CURRENT_SOURCE_DIR}/${_spec_file} native-spec2def)
+    set_source_files_properties(${CMAKE_CURRENT_BINARY_DIR}/${_file}.def PROPERTIES EXTERNAL_OBJECT TRUE)
     
     if(__add_importlib)
         # Generate the asm stub file and the export def file for import library