KB4594443

System and user certificates might be lost when updating a device from Windows 10, version 1809 or later to a later version of Windows 10. 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 This primarily happens when managed devices are updated using outdated bundles or media through an update management tool such as Windows Server Update Services (WSUS) or Microsoft Endpoint Configuration Manager. This might also happen when using outdated physical media or ISO images that do not have the latest updates integrated.

Note Devices using Windows Update for Business or that connect directly to Windows Update are not impacted. Any device connecting to Windows Update should always receive the latest versions of the feature update, including the latest LCU, without any extra steps.

This issue is resolved in KB4592449.