Software Update Error 0x80004005 on client systems

Just when you thought you've seen all known issues, you get another one. This time a client didn't get updates for several months. In almost all Software Update logfiles (UpdatesDeployment.log, WindowsUpdate.log, WUAHandler.log) the error message is the same: Software Update Error: 0x80004005. In the CCMCache no updates where found for several months. This for both Windows updates and Endpoint Protection (SCEP) updates.

The UpdatesDeployment.log shows:
Job error (0x80004005) received for assignment ({<?>}) action
Updates will not be made available

The WindowsUpdate.log shows:
WinHttp: SendRequestToServerForFileInformation failed with 0x801901f7
WinHttp: ShouldFileBeDownloaded failed with 0x801901f7

The WUAHandler.log shows:
Unable to find or read WUA Managed server policy.
Unable to read existing WUA Group Policy object. Error = 0x80004005.
Enabling WUA Managed server policy to use server: <?>
Failed to Add Update Source for WUAgent of type (2) and id ({<?>}). Error = 0x80004005.

Lucky me I found the following blogpost: Microsoft TechNet
It mentions: Had the same issue.  Issue appears to be with corrupt policy info locally on the machine. Typically going to C:\Windows\System32\GroupPolicy\Machine and delete Registry.pol  As soon as I do that I can tell the client to perform an updates scan and all is well. More than likely there is a more elegant solution, but that resolves this error message for me.

I did found indeed a Registry.pol file, which was updated several months ago. I deleted the file, and did a GPUpdate /force after that. When starting Machine policy retrieval after that you will see that the error is gone. I installed 1GB on updates after that :-)