Windows 8.1/Server 2012 R2: KB5003681 blocks Defender real-time protection (Error 0x800705b4)

Windows[German]After installing the June 2021 security update KB5003681 (Security Only Quality), some users are finding that Windows Defender's real-time protection no longer opens on Windows 8.1 and Windows Server 2012 R2. After uninstalling the update, everything works again. However, there may be a workaround.


Security Only Quality Update KB5003681

Security Only Quality Update KB5003681 for Windows 8.1 and Windows Server 2012 R2 addresses a number of vulnerabilities in Windows components.

Security updates to Windows App Platform and Frameworks, Windows Cloud Infrastructure, Windows Authentication, Windows Fundamentals, and Windows Storage and Filesystems.

I had mentioned the update in the blog post Patchday: Windows 8.1/Server 2012 updates (June 8, 2021). 

Defender real-time protection cannot be activated

Within my German blog post, various readers have reported having Defender real-time protection disabled by the update. The attempt to re-enable the real-time protection in the maintenance center fails due to timeout with error code 0x800705b4. Blog reader Klaus Pit writes:

After the "Security-only update" the real-time protection of the Defender is deactivated. The attempt to reactivate in the maintenance center fails due to timeout.


If I uninstall the update, everything is fine again. What should I do?

Klaus then installed the Monthly Rollup Update at the end of the day and everything worked again. There are other readers who report exactly this problem in the comments. 

Possible workaround

Besides the installation of the Monthly Rollup Update I found this article on the internet. There it says that in the registry in the branch:


HKEY_LOCAL_MACHINE\SOFTWARE\Policies\Microsoft\Windows Defender

you should check the DisableAntiSpyware DWORD value. If the value is set to 1, you should reset it to 0. Alternatively, the key is:

HKEY_LOCAL_MACHINE\SOFTWARE\Policies\Microsoft\Windows Defender

(this is where the group policy settings for Defender are managed). Maybe it will help.

This article still addresses some registry entries, but they are related to Windows Defender Application Guard or Windows Sandbox in Windows 10, which should not help in Windows 8.1.

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