Windows 10 Patch Tuesday (KB5012599) is out — here's what's new and what's broken

Devices with Windows installations
created from custom offline media or
custom ISO image might have Microsoft Edge
Legacy removed by this update, but not
automatically replaced by the new
Microsoft Edge. This issue is only
encountered when custom offline media or ISO images are created by
slipstreaming this update into the image without having first installed the
standalone servicing stack update (SSU)
released March 29, 2021
or later.

Note Devices that connect directly to
Windows
Update to receive updates are not
affected. This includes devices using Windows Update for
Business. Any device connecting to
Windows Update should always receive
the latest versions of the SSU and latest
cumulative update (LCU) without any
extra steps.

To avoid this issue, be sure to first slipstream
the SSU released March 29, 2021 or later into
the custom offline media or ISO image before
slipstreaming the LCU. To do this with the
combined SSU and LCU packages now used for Windows 10, version 20H2 and Windows 10,
version 2004, you will need to extract the SSU
from the combined package. Use the following
steps to extract the SSU:

1. Extract the cab from the msu via this command line (using the package for KB5000842 as an example): expand Windows10.0-KB5000842-x64.msu /f:Windows10.0-KB5000842-x64.cab
2. Extract the SSU from the previously extracted cab via this command line: expand Windows10.0-KB5000842-x64.cab /f:*

3. You will then have the SSU cab, in this example named SSU-19041.903-x64.cab. Slipstream this file into your offline image first, then the LCU.

    

If you have already encountered this issue by installing the OS using affected custom media, you can mitigate it by directly installing the new Microsoft Edge. If you need to broadly deploy the new Microsoft Edge for business, see Download and deploy Microsoft Edge for business.

After installing the June 21, 2021 (KB5003690) update, some devices cannot install new updates, such as the July 6, 2021 (KB5004945) or later updates. You will receive the error message, "PSFX_E_MATCHING_BINARY_MISSING".

For more information and a workaround, see KB5005322.

After installing this update, when connecting to devices in an untrusted domain using Remote Desktop, connections might fail to authenticate when using smart card authentication. You might receive the prompt, "Your credentials did not work. The credentials that were used to connect to [device name] did not work. Please enter new credentials." and "The login attempt failed" in red.

This issue is resolved using Known Issue Rollback (KIR). Please note that it might take up to 24 hours for the resolution to propagate automatically to non-managed personal devices and non-managed business devices. Restarting your Windows device might help the resolution apply to your device faster. For enterprise-managed devices that have installed an affected update and encountered this issue, it can be resolved by installing and configuring a special Group Policy linked below.

Note Devices need to be restarted after configuring the special Group Policy. For help, please see How to use Group Policy to deploy a Known Issue Rollback. For general information on using Group Policies, see Group Policy Overview.

Group Policy installation files:

• Windows Server 2022

   

• Windows 10, version 2004, Windows 10, version 20H2, Windows 10, version 21H1, and Windows 10, version 21H2

   

Important Verify that you are using the correct Group Policy for your version of Windows.

KB5012591

18363.2212

KB5012647

17763.2803

Long Term Servicing Channel (LTSC)

KB5012596

14393.5066

KB5012653

10240.19265