Those who having the problem with Update prompt thing, they can UNCHECK the "Check for updates automatically" box under the General section, and most probably, the prompt won't come. Those who say, utorrent trigger their anti virus, it's not utorrent, it's the files you are downloading (.torrent file), might have suspicious files which possibly could trigger the Anti Virus scan, as Anti Virus have Realtime Protection/File Scanning system. So they check every incoming files, as soon they start to come.