diff --git a/win32ss/user/user32/windows/defwnd.c b/win32ss/user/user32/windows/defwnd.c
index 563005a42c2..27dcc574c51 100644
--- a/win32ss/user/user32/windows/defwnd.c
+++ b/win32ss/user/user32/windows/defwnd.c
@@ -11,6 +11,9 @@
 
 #include <user32.h>
 
+#include <wine/debug.h>
+WINE_DEFAULT_DEBUG_CHANNEL(user32);
+
 /*
  * @implemented
  */