diff --git a/src/remote/os/win32/window.cpp b/src/remote/os/win32/window.cpp
index 105200ca8d..3d63295f37 100644
--- a/src/remote/os/win32/window.cpp
+++ b/src/remote/os/win32/window.cpp
@@ -39,6 +39,7 @@
 #include "../remote/os/win32/window_proto.h"
 #include "../remote/os/win32/propty_proto.h"
 #include "../jrd/gds_proto.h"
+#include "../jrd/why_proto.h"
 
 #include "../remote/os/win32/window.h"
 #include "../jrd/isc_proto.h"