diff --git a/libs/ardour/MSVClibardour/ardour.vcproj b/libs/ardour/MSVClibardour/ardour.vcproj
index 697bc9d306..ec95b36c22 100644
--- a/libs/ardour/MSVClibardour/ardour.vcproj
+++ b/libs/ardour/MSVClibardour/ardour.vcproj
@@ -287,6 +287,10 @@
 				RelativePath="..\async_midi_port.cc"
 				>
 			</File>
+			<File
+				RelativePath="..\audio_backend.cc"
+				>
+			</File>
 			<File
 				RelativePath="..\audio_buffer.cc"
 				>