I have a recently-built Windows Server 2008 R2 system whose Windows Updates started failing suddenly. While I am presented an error code 80072F76, none of the automatic fixes seem to work.

What's the best method to troubleshoot this? General internet access works as normal.

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  • Is Automatically detect settings check box is selected in the LAN settings? IE > Tools > Internet Options > Connections > LAN Settings – colealtdelete Apr 29 '13 at 14:47
  • @cole Yes. It's checked. – ewwhite Apr 29 '13 at 14:48
  • Can you reboot the server? I've seen this issue before where it wouldn't connect (usually on a new installation) and a reboot usually fixes it. – colealtdelete Apr 29 '13 at 14:54
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    Is there a WSUS server on the network by chance? And are your firewalls running any IDS software on them? I've seen (with Sonicwalls) that the IDS signatures will occasionally flag and block windows update traffic. – David V Apr 29 '13 at 14:56
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    I've also seen Kaspersky Antivirus stop updates from happening, or the Windows Update service is set to manual. – colealtdelete Apr 29 '13 at 14:59

And I found the source... a Barracuda Web Filter set to block Windows Updates...

Soooo wrong (another admin configured this)...

Administrators should understand this this is a poor way of managing bandwidth.

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  • Barracuda is just that smart. – Brock Hensley Apr 29 '13 at 15:04
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    Maybe it was done on purpose because WSUS. Proper GPO might still be needed. (Although that block sure looks global to me) – TheCleaner Apr 29 '13 at 15:09
  • No WSUS, no AD domain (yet) and yes, it was a blanket global URL block. – ewwhite Apr 29 '13 at 15:12
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    Maybe the admin thought Windows Updates were on par with thedirty.com ;) – TheCleaner Apr 29 '13 at 15:17

The general place to start troubleshooting this error is KB836941. Following the steps in this KB article may resolve the problem, but probably won't, since the article indicates that 0x80072F76 corresponds to an API error ERROR_WINHTTP_HEADER_NOT_FOUND. This error, it turns out, means that there is an HTTP header that Windows Update is looking for but wasn't present in the response.

This, of course, indicates that Windows Update didn't actually connect successfully to the Windows Update server, but something in the middle interfered with the connection.

To resolve the issue, check the proxy servers and firewalls in the path between the server and the Internet to determine which one is blocking or mangling the connection. Also check for viruses and malware, as some of them target Windows Update to prevent updates from being installed.

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