--- a/widget/windows/nsWindow.cpp
+++ b/widget/windows/nsWindow.cpp
@@ -5053,18 +5053,22 @@ nsWindow::ProcessMessage(UINT msg, WPARA
         cancelQuit->GetData(&abortQuit);
         sCanQuit = abortQuit ? TRI_FALSE : TRI_TRUE;
       }
       *aRetValue = sCanQuit ? TRUE : FALSE;
       result = true;
       break;
 
     case MOZ_WM_STARTA11Y:
+#if defined(ACCESSIBILITY)
       (void*)GetAccessible();
       result = true;
+#else
+      result = false;
+#endif
       break;
 
     case WM_ENDSESSION:
     case MOZ_WM_APP_QUIT:
       if (msg == MOZ_WM_APP_QUIT || (wParam == TRUE && sCanQuit == TRI_TRUE))
       {
         // Let's fake a shutdown sequence without actually closing windows etc.
         // to avoid Windows killing us in the middle. A proper shutdown would