diff --git a/src/w32fns.c b/src/w32fns.c
index 1b628b0b42e..dd16d74439f 100644
--- a/src/w32fns.c
+++ b/src/w32fns.c
@@ -4801,7 +4801,11 @@ w32_wnd_proc (HWND hwnd, UINT msg, WPARAM wParam, LPARAM lParam)
 
     case WM_ENDSESSION:
       my_post_msg (&wmsg, hwnd, msg, wParam, lParam);
-      /* If we return, the process will be terminated immediately.  */
+      /* Allow time for Emacs to attempt an orderly shutdown.  If we
+         return, the process will be terminated immediately.  FIXME:
+         1000 seconds is too long to sleep if the shutdown attempt
+         fails (see bug#25875).  But if it fails, we want to find out
+         about it, so let's leave 1000 for now.  */
       sleep (1000);
 
     case WM_WINDOWPOSCHANGING: