You may lose system certificates after Patch Tuesday updates

Vlad Turiceanu
by Vlad Turiceanu
Editor-in-Chief
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  • The monthly Patch Tuesday updates for November have been released for most Windows 10 users.
  • If you’re one of them as well, do note that they may cause some issues related to system certificates.
  • To discover more about Microsoft's scheduled security fix releases, visit our Patch Tuesday section.
  • Your OS is better than ever, so use this Windows 10 section to explore it and discover its features.
November Patch Tuesday

The release of this month’s Patch Tuesday updates is of major interest to Windows 10 v2004, Windows 10 1909, and 1903 users.

Simply put, it fixes issues identified in the software program you run on a regular basis and brings major security improvements.

Unlike regular updates that rarely demand much attention, Patch Tuesday updates involve a much bigger process.

In spite of that, certain issues do arise. System and user certificates might be lost when users update their PC from Windows 10, version 1809 or later to a later version of Windows 10.


October Patch Tuesday may cause system certificate issues

Microsoft has recently distributed a new cumulative update KB4586781 to its users via Windows Update and WSUS.

This non-security patch increases the build numbers of version 2004 to 19041.630 and version 20H2 to 19042.630.

According to the official Microsoft changelog regarding the KB4586781 cumulative updates, it seems that they may lead to problems related to system and user certificates:

Devices will only be impacted if they have already installed any Latest cumulative update (LCU) released September 16, 2020 or later and then proceed to update to a later version of Windows 10 from media or an installation source which does not have an LCU released October 13, 2020 or later integrated.

This primarily happens when managed devices are updated using outdated bundles or media through an update management tool such as Windows Server Update Services (WSUS) or Microsoft Endpoint Configuration Manager.

Things are no different for KB4586786 cumulative updates (OS builds 18362.1198 and 18363.1198). If you are also bothered by this issue, feel free to mitigate it within the uninstall window by going back to your previous version of Windows.


That covers our topic for today. If you need a summary of the November Patch Tuesday, we have written this dedicated article that includes the download links that you can use to get the updates right away.

The next Patch Tuesday falls on December 8, so rest assured that we’ll return with new details. Until then, enjoy your patching and make sure to keep your PC safe from the latest threats.

Moreover, don’t hesitate to let us know whether or not you intend to apply the cumulative updates immediately. Do so by using the comments area below.

  • A week ago i got KB4586786. After that my email client (Claws Mail) freezes after starting it. Had to terminate it in Task Manager. After uninstalling KB4586786, no problems.

    Yesterday while shutting down my PC i got KB4586786 again. And today my email client did not work again. After uninstalling KB4586786 no problems.