diff --git a/src/calibre/gui2/main.py b/src/calibre/gui2/main.py
index 9f1bcf3506..51c310c1f9 100644
--- a/src/calibre/gui2/main.py
+++ b/src/calibre/gui2/main.py
@@ -417,7 +417,7 @@ def run_gui(opts, args, listener, app, gui_debug=None):
     return ret
 
 
-singleinstance_name = 'calibre_GUI'
+singleinstance_name = 'GUI'
 
 
 def cant_start(msg=_('If you are sure it is not running')+', ',