KB5027231: Fix CopyFile Api problem with 32 bit application

Highlights

• This update fixes security issues for your Windows operating system.

Improvements

This security update contains improvements that were part of update KB5026446 (released May 24, 2023). When you install this KB:

• This update fixes a known issue that affects 32-bit apps that support large addresses and use the CopyFile API. You may experience issues when saving, copying, or appending files. If you use commercial or enterprise security software that uses extended file attributes, this issue likely affects you. For Microsoft Office apps, this issue affects only the 32-bit versions. You may receive the error message "Document was not saved".
• This update fixes a compatibility issue. The issue occurs because the registry is not supported.
• This update resolves an issue that affects the Windows kernel. This issue is related to CVE-2023-32019. For more information, see KB5028407.

If you installed earlier updates, only the new updates in this package are downloaded and installed on your device.

For more information about security risks, see the Security Update Guide website and the June 2023 Security Update.

Windows 11 Maintenance Stack Update - 22621.1771

This update contains qualitative improvements to the servicing stack, which is the component that installs Windows updates. SSU (Servicing Stack Updates) ensure that you have a robust and reliable maintenance stack so that your devices can receive and install Microsoft updates.

Known issues with this update

• Using deployment packages on Windows 11, version 22H2 (also referred to as Windows 11 2022 update) may not work as expected. Windows may be only partially configured, and the initial run setup may not complete or may restart unexpectedly. Deployment packages are .PPKG files that are used to configure new devices for use on business, school, or university networks. Provisioning packages that are applied during initial setup are most likely to be affected by this issue. For more information about deployment packages, see Deployment packages for Windows.

**Note Deploying Windows devices with Windows Autopilot is not affected by this issue.

Windows devices used by consumers at home or in small offices are not likely to be affected by this issue.