diff --git a/src/server/shared/Memory.h b/src/server/shared/Memory.h
index ac697f7a1af..25533638915 100644
--- a/src/server/shared/Memory.h
+++ b/src/server/shared/Memory.h
@@ -3,6 +3,8 @@
 #ifndef _MEMORY_H
 #define _MEMORY_H
 
+#include "DetourAlloc.h"
+
 //  memory management
 inline void* dtCustomAlloc(int size, dtAllocHint /*hint*/)
 {