diff --git a/src/ChangeLog b/src/ChangeLog
index 89f5e0ee64d..c48956042a1 100644
--- a/src/ChangeLog
+++ b/src/ChangeLog
@@ -1,3 +1,8 @@
+2011-07-08  Jason Rumney  <jasonr@gnu.org>
+
+	* w32fns.c (w32_wnd_proc) [WM_TIMER, WM_SET_CURSOR]: Avoid using
+	frame struct members of non-existent frames (Bug#6284).
+
 2011-07-08  Jan Djärv  <jan.h.d@swipnet.se>
 
 	* nsterm.m (keyDown): Call to wantsToDelayTextChangeNotifications and
diff --git a/src/w32fns.c b/src/w32fns.c
index cba0b91e685..f48e5764b4c 100644
--- a/src/w32fns.c
+++ b/src/w32fns.c
@@ -3273,7 +3273,8 @@ w32_wnd_proc (HWND hwnd, UINT msg, WPARAM wParam, LPARAM lParam)
 	    {
 	      /* Free memory used by owner-drawn and help-echo strings.  */
 	      w32_free_menu_strings (hwnd);
-	      f->output_data.w32->menubar_active = 0;
+	      if (f)
+		f->output_data.w32->menubar_active = 0;
               menubar_in_use = 0;
 	    }
 	}
@@ -3623,10 +3624,10 @@ w32_wnd_proc (HWND hwnd, UINT msg, WPARAM wParam, LPARAM lParam)
       if (LOWORD (lParam) == HTCLIENT)
 	{
 	  f = x_window_to_frame (dpyinfo, hwnd);
-	  if (f->output_data.w32->hourglass_p && !menubar_in_use
-	      && !current_popup_menu)
+	  if (f && f->output_data.w32->hourglass_p
+	      && !menubar_in_use && !current_popup_menu)
 	    SetCursor (f->output_data.w32->hourglass_cursor);
-	  else
+	  else if (f)
 	    SetCursor (f->output_data.w32->current_cursor);
 	  return 0;
 	}