diff --git a/libs/ardour/MSVClibardour/ardour.vcproj b/libs/ardour/MSVClibardour/ardour.vcproj
index 9b72773188..ff404f3475 100644
--- a/libs/ardour/MSVClibardour/ardour.vcproj
+++ b/libs/ardour/MSVClibardour/ardour.vcproj
@@ -1753,6 +1753,10 @@
 				RelativePath="..\ardour\io_processor.h"
 				>
 			</File>
+			<File
+				RelativePath="..\ardour\io_vector.h"
+				>
+			</File>
 			<File
 				RelativePath="..\ardour\kmeterdsp.h"
 				>