diff --git a/src/calibre/srv/standalone.py b/src/calibre/srv/standalone.py
index dd22a27ee3..13ca01b45b 100644
--- a/src/calibre/srv/standalone.py
+++ b/src/calibre/srv/standalone.py
@@ -113,7 +113,7 @@ libraries that the main calibre program knows about will be used.
             '--daemonize',
             default=False,
             action='store_true',
-            help=_('Run process in background as a daemon.'))
+            help=_('Run process in background as a daemon (Linux only).'))
     parser.add_option(
         '--pidfile', default=None, help=_('Write process PID to the specified file'))
     parser.add_option(