Microsoft released the first Windows 10 21H1 build for Windows Insiders on the beta channel that have opted in to 21H1. The update contains all the fixes from 19042.844 for 20H2 and some additional changes:
Windows Hello multicamera support to set the default as the external camera when both external and internal Windows Hello cameras are present.
Windows Defender Application Guard performance improvements including optimizing document opening scenario times.
We fixed an issue that causes a one minute or more delay when you open a Microsoft Defender Application Guard (WDAG) Office document. This occurs when you try to open a file using a Universal Naming Convention (UNC) path or Server Message Block (SMB) share link.
We improved Robocopy’s performance when copying files that total over 400 MB in size.
We fixed an issue that causes a WDAG container to use almost 1 GB of memory (working set) when the container is idle.
Windows Management Instrumentation (WMI) Group Policy Service (GPSVC) updating performance improvement to support remote work scenarios.
We fixed an issue that causes changes that the Active Directory (AD) administrator makes to user or computer group membership to propagate slowly. Although the access token eventually updates, these changes do not appear when the administrator uses gpresult /r or gpresult /h to create a report.