Microsoft August 2020 Patchday issues

[German]The security updates rolled out by Microsoft on August 11, 2020 for Windows and other Microsoft products are causing problems for some users. These range from installation errors 0x800f0988 to login problems to Hyper-V machines that no longer work. There is an update for the striking PDF24 Creator which fixes the error.


I had reported about the various security updates in the blog posts linked at the end of the article. Here is some information about what you should know and what problems have come to my attentioneyes.

Install Internet Explorer Update KB4571687!

For users who are running Windows 7 SP1 or Windows 8.1 and the server counterparts on the security-only updates, be sure to install the cumulative security update for Internet Explorer 11 KB4571687. Kaspersky has published an article about the vulnerabilities here. The security update fixes several vulnerabilities described in the support article. Meanwhile it has been reported that an attacker is attacking systems via two 0-day exploits in Internet Explorer 11. These vulnerabilities have been closed with the August 2020 IE update.

Issues with Windows 10 Update KB4566782

Cumulative update KB4566782 for Windows 10 Version 2004 and for Windows Server Version 2004 causes different errors for different users. Here is a short outline.

Windows 10 update KB4566782 throws errors 0x800f0988

At there is this post, which indicates that there are first reports that the installation fails with the error code 0x800f0988. The following text was posted there:

The update KB4566782 is not working 0x800f0988:

Exec: Failed to pre-stage package: Microsoft-Windows-WindowsMediaPlayer-Troubleshooters-Package~31bf3856ad364e35~amd64~~10.0.19041.1,
component identity: amd64_adobe-flash-for-windows_31bf3856ad364e35_10.0.19041.1_none_e190f18a08ed1a44,
file: Flash.ocx, sandbox: \?\C:\WINDOWS\CbsTemp\30830624_112917922\,
file format: 0 [HRESULT = 0x800f0988 – PSFX_E_INVALID_DELTA_COMBINATION]

I had given some hints in the blog post Windows 10: KB4551762 causes error 0x800f0988/0x800f0900 and also wrote: If nothing helps, do an Inplace Upgrade. Because the whole thing points to a damaged WinSxS folder. German blog- eader Peter A. was affected by this bug and was able to save his system via in-place upgrade.


Applications fails or are slow

German blog reader reported here, that since the installation of KB4566782 and KB4569745 the NordVPN Client does not start anymore. Other users report about other apps that are won't launch (see the comment here about .NET Framework updates). This Microsoft Answers forum thread complains about several bugs like slow start or black login screen.

PDF24 Creator broken

In addition, the PDF24 Creator no longer works, as the discussions in their forum show. There the developer has made improvements, because as you can read here, this bug is fixed with the PDF24 Creator 9.2.0.

Network access to shares

In this German comment someone complains that the KB4566782 cumulative update caused network problems. He could no longer copy folders from the network to the local drive. After uninstalling the update, everything works again. Seems to be an isolated case, though.

Update KB4571694 breaks AD authentification

A German blog reader left a comment, that update KB4571694 for Windows 10 Version 1607 breaks the authentication of all Windows Server 2016 and their services against the Active Directory (AD). Uninstalling the update fixed this issues.

Update breaks Hyper-V

The August 2020 updates appear to be causing issues with Hyper-V machines for some users. In my German blog you can find this comment about this problem:

Mhh so on Windows Server 2019 1809 one of the updates shoots Hyper-V – VMs don't start anymore, Hyper-V manager doesn't work neither GUI nor PS – total fuck up

Now I have uninstalled the updates one by one, all VMs except one are running again but it's not ok yet – the manager needs minutes to load the VMs and starting saved VMs takes forever, otherwise it takes seconds – but for tonight I'm fed up.

And also at German site I found this entry which deals with Hyper-V problems with Windows Server 2019. If you have other bugs or know a solution, leave a comment.

Similar articles:
Microsoft Office Patchday (August 4, 2020)
Microsoft Security Update Summary (August 11, 2020)
Patchday: Windows 10-Updates (August 11, 2020)
Patchday: Windows 8.1/Server 2012-Updates (August 11, 2020)
Patchday: Updates for Windows 7/Server 2008 R2 (August 11, 2020)
Patchday Microsoft Office Updates (August 11, 2020)

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3 Responses to Microsoft August 2020 Patchday issues

  1. Brad Johnson says:

    This update also breaks every version of RightFax software.
    The problem is it breaks \\.\pipe\ for RightFax software.
    RightFax is looking for the fix currently to see if they can mitigate the issue.
    Even if you remove the patch it does not fix the issue.
    Microsoft has been notified of the issue.
    It does not seem to break \\.\pipe\docker_engine as our Portainer instances still work.

  2. Nazim Rajani says:

    Had a really weird issue after installing this patch on Windows 2016 PDC on the weekend. This morning all the Domain PC's including Servers were not able to connect to the Fileshare with IP Address. However, Fileshare access worked perfectly fine when trying to browse via Hostname.

    This issue got fixed after uninstalling the patch. From a Domain PC when trying to access the network share via IP we were getting issue such as "The local device name is already in use" and "The trust relationship between this workstation and the primary domain failed."

    Has anyone else encountered these issues?

  3. Joseph says:

    This happened to me today,I had this update and no errors so far,but when I decided to plug in the charger,5 minutes later,kernel panic Bsod(secure kernel error)it didn't restart it self,it got frozen,I had to force restart it,its back to normal for now,Lenovo T490

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