http://blogs.technet.com/b/clientsecurity/archive/2010/02/26/checking-for-definition-updates-when-starting.aspxNext up in our registry key series: enabling definition updates upon service start. By default (out of box), the FCS client will check for definition updates: Before starting a scan At the configured interval Manually However, thereen-USTelligent Evolution Platform Developer Build (Build: 5.6.50428.7875)http://blogs.technet.com/b/clientsecurity/archive/2010/02/26/checking-for-definition-updates-when-starting.aspx#3339748Tue, 22 Jun 2010 17:14:40 GMTd5e57398-b9ef-4490-9955-07cbb4e4a80d:3339748Kimborly A. Ditto-Ehlert<p>Hi Tim,</p> <p>Take a look in your Windowsupdate.log to see if htere is a failure reason in there... (search for Error).</p> <p>Thanks for your comment!</p> <div style="clear:both;"></div><img src="http://blogs.technet.com/aggbug.aspx?PostID=3339748" width="1" height="1">http://blogs.technet.com/b/clientsecurity/archive/2010/02/26/checking-for-definition-updates-when-starting.aspx#3339163Sat, 19 Jun 2010 04:58:25 GMTd5e57398-b9ef-4490-9955-07cbb4e4a80d:3339163tim<p>{4027D370-9463-4E54-A0F8-5368E382C211} 2010-06-18 07:09:26:627+0800 1 182 101 {F16C5EE3-8676-41D2-99D8-EEA92B049B4B} 100 80070643 Microsoft Forefront Client Secu Failure Content Install Installation Failure: Windows failed to install the following update with error 0x80070643: Definition Update for Microsoft Forefront Client Security - KB977939 (Definition 1.85.111.0).</p> <div style="clear:both;"></div><img src="http://blogs.technet.com/aggbug.aspx?PostID=3339163" width="1" height="1">http://blogs.technet.com/b/clientsecurity/archive/2010/02/26/checking-for-definition-updates-when-starting.aspx#3339162Sat, 19 Jun 2010 04:45:58 GMTd5e57398-b9ef-4490-9955-07cbb4e4a80d:3339162tim<p>on standalone computer running Win7 pro x67, when fcs update at startup is always fail to install definition with error 0x80070643.</p> <div style="clear:both;"></div><img src="http://blogs.technet.com/aggbug.aspx?PostID=3339162" width="1" height="1">