diff --git a/win_build/libboincapi.vcproj b/win_build/libboincapi.vcproj
index a77606d4bd..b3a3213c05 100644
--- a/win_build/libboincapi.vcproj
+++ b/win_build/libboincapi.vcproj
@@ -464,6 +464,10 @@
 				RelativePath="..\..\boinc\api\gutil.h"
 				>
 			</File>
+			<File
+				RelativePath="..\..\boinc\api\reduce.h"
+				>
+			</File>
 			<File
 				RelativePath="..\..\boinc\api\texfont.h"
 				>