diff -uNr calibre.old/src/calibre/gui2/ui.py calibre/src/calibre/gui2/ui.py
--- calibre.old/src/calibre/gui2/ui.py	2011-01-11 22:08:00.684511166 +0100
+++ calibre/src/calibre/gui2/ui.py	2011-01-11 22:11:34.522099663 +0100
@@ -648,7 +648,7 @@
         if write_settings:
             self.write_settings()
         self.check_messages_timer.stop()
-        self.update_checker.terminate()
+        # self.update_checker.terminate()
         self.listener.close()
         self.job_manager.server.close()
         while self.spare_servers:
diff -uNr calibre.old/src/calibre/gui2/update.py calibre/src/calibre/gui2/update.py
--- calibre.old/src/calibre/gui2/update.py       2011-06-19 01:26:50.719502823 +0300
+++ ucalibre/src/calibre/gui2/update.py   2011-06-17 20:56:05.000000000 +0300
@@ -123,11 +123,11 @@
 
     def __init__(self, opts):
         self.last_newest_calibre_version = NO_CALIBRE_UPDATE
-        if not opts.no_update_check:
-            self.update_checker = CheckForUpdates(self)
-            self.update_checker.update_found.connect(self.update_found,
-                    type=Qt.QueuedConnection)
-            self.update_checker.start()
+    #    if not opts.no_update_check:
+    #        self.update_checker = CheckForUpdates(self)
+    #        self.update_checker.update_found.connect(self.update_found,
+    #                type=Qt.QueuedConnection)
+    #        self.update_checker.start()
 
     def recalc_update_label(self, number_of_plugin_updates):
         self.update_found('%s%s%d'%(self.last_newest_calibre_version, VSEP,