diff --git a/src/protocols/rdp/channels/rail.c b/src/protocols/rdp/channels/rail.c
index 2fbac78a9..276f6ee2e 100644
--- a/src/protocols/rdp/channels/rail.c
+++ b/src/protocols/rdp/channels/rail.c
@@ -292,7 +292,7 @@ static BOOL guac_rdp_rail_window_update(rdpContext* context,
         }
     }
 
-    return true;
+    return TRUE;
 
 }