diff --git a/Doc/library/winsound.rst b/Doc/library/winsound.rst
index 2325081..5c590ff 100644
--- a/Doc/library/winsound.rst
+++ b/Doc/library/winsound.rst
@@ -133,6 +133,10 @@
 
    Return immediately if the sound driver is busy.
 
+   .. note::
+
+      This flag is not supported on modern Windows platforms.
+
 
 .. data:: MB_ICONASTERISK