Windows 10 Version 1607: Windows Update error 0x80D05001

[German]Some users of Windows 10 are running into trouble with Windows Update, after upgrading to Windows 10 Version 1607 (Anniversary Update). Windows Update returns an error code 0x80D05001.

I've addressed this error within my blog post Windows 10: Store downloads causes error 0x80D05001, but it was related to Windows 10 store. Nevertheless, this article can deliver a clue, what's wrong with the system. Error code 0x80D05001 stands for DO_E_HTTP_BLOCKSIZE_MISMATCH. Third party tools, that establish an own proxy server, are the root cause for this error 0x80D05001.

Check the proxy server settings

So check whether third party Internet Security Suites or VPN software is installed. If that's true, one repair attempt (obtained from the linked blog post above) is to check the settings for the proxy server used in Windows. Here are the steps.

1. Press Windows + R to invoke the Run dialog box and type inetcpl.cpl. Click OK to execute this command.

2. Click the Connections tab, and then click the LAN settings button.

3. In Local Area Network (LAN) Settings dialog uncheck the box Use a proxy server for your LAN (..).

The close the dialog box and the tab using the OK button. Then try a reboot and check, if the issue has been fixed.

The steps to reset the proxy settings in Internet Explorer is also discussed inKB2289942. If your application requires a proxy server, read KB3175743, and set the proxy rules according to the requirements defined in the KB article.

Same problem with a hardware firewall

Recently I stumbled uppon this Technet forum thread, where the same error code 0x80D05001 has been mentioned together with Windows Update. The user reports that the error occurs after upgrading some Windows 10 clients from version 1511 to version 1607 (Anniversary Update). 

since upgrading to Windows 10 version 1607 updating our clients fails with error code 80d05001.

I could narrow it down to our firewall that does http and https inspection. That seems quite weird as it was working properly with version 1511. According to the logs the issue may be caused by update delivery via file streaming.

Activating the Delivery Optimization (p2p) in Windows 10 Anniversary Update did not help. The user reported that he was able to track the issue down to the following root cause:

It seems Windows 10 does not use standard conform MIME-types for downloading since version 1607.

They used a hardware firewall from Sophos, which blocked all connections from Windows 10 Clients to Microsoft's Windows Update servers. They had to set some exception in their Sophos hardware firewall as a regex-expressions:

^https?://([A-Za-z0-9.-]*\.)?windowsupdate\.com/
^https?://([A-Za-z0-9.-]*\.)?microsoft\.com/

Afterward Windows Update was able to pull updates under Windows 10 Anniversary Update.

Microsoft details proxy requirements for Windows Update

I found also this MS Answers forum thread with a similar case. They are using a SonicWall firewall apliance, and a Windows Defender definition  update error 0x80D05001 occurs on clients. Within the thread is a reference to KB3175743, where Microsoft details the Proxy requirements for Windows Update for Windows 10 Anniversary Update. 

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