diff --git a/audio/CMakeLists.txt b/audio/CMakeLists.txt
index bca7e40..7e8203c 100644
--- a/audio/CMakeLists.txt
+++ b/audio/CMakeLists.txt
@@ -6,6 +6,11 @@ target_include_directories(audio_lib INTERFACE
     "${CMAKE_CURRENT_SOURCE_DIR}"
 )
 
+SET_SOURCE_FILES_PROPERTIES(pcfx.obj PROPERTIES
+    EXTERNAL_OBJECT true
+    GENERATED true
+)
+
 target_link_libraries(audio_lib INTERFACE
     "${CMAKE_CURRENT_SOURCE_DIR}/audio_wf.lib"
     "${CMAKE_CURRENT_SOURCE_DIR}/pcfx.obj"