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.
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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