diff --git a/libs/surfaces/osc/MSVCardour_osc/ardour_osc.vcproj b/libs/surfaces/osc/MSVCardour_osc/ardour_osc.vcproj
index 6a68e7476d..c542d2387c 100644
--- a/libs/surfaces/osc/MSVCardour_osc/ardour_osc.vcproj
+++ b/libs/surfaces/osc/MSVCardour_osc/ardour_osc.vcproj
@@ -279,6 +279,10 @@
 				RelativePath="..\osc_controllable.cc"
 				>
 			</File>
+			<File
+				RelativePath="..\osc_gui.cc"
+				>
+			</File>
 			<File
 				RelativePath="..\osc_route_observer.cc"
 				>