diff --git a/r5dev/core/stdafx.h b/r5dev/core/stdafx.h
index e6c44300..77b4695a 100644
--- a/r5dev/core/stdafx.h
+++ b/r5dev/core/stdafx.h
@@ -35,6 +35,8 @@
 #include <set>
 #include <unordered_set>
 
+#include <smmintrin.h>
+
 // Windows specifics.
 #ifndef FILE_SUPPORTS_GHOSTING
 #define FILE_SUPPORTS_GHOSTING 0x40000000  // winnt