Windows 11 KB5040527 update fixes Windows Backup failures

Microsoft has released the optional KB5040527 preview cumulative update for Windows 11 23H2 and 22H2, which includes fixes for Windows Backup and upgrade failures.

The July 2024 non-security preview update fixes an issue that sometimes caused Windows backups to fail on devices with an Extensible Firmware Interface (EFI) system partition (ESP).

It also addresses a known Windows Enterprise subscription issue, which caused upgrades from Windows Professional to fail with 0x80070005 "access denied" errors in the LicenseAcquisition scheduled task.

Additionally, KB5040527 fixes a Windows Defender Application Control (WDAC) memory leak that could lead to system memory exhaustion while provisioning Windows devices and a separate WDAC bug that triggers app failures when applying WDAC Application ID policies.

You can install this preview update by clicking on 'Check for Updates" after going into Settings > Windows Update. Given that this is an optional update, you will be asked if you want to install it by clicking the 'Download and install' link.

You can also manually download and install KB5040527 from the Microsoft Update Catalog.

Windows 11 KB5040527 highlights

This preview release includes additional fixes and improvements and will update Windows 11 22H2 and 23H2 to builds 22621.3958 and 22631.3958.

This month's non-security preview update also comes with additional fixes for:

• An issue with the Print Support App: when you use it with a USB device, it stops responding and does not print. This issue also limits the functions of the user interface.
• An issue with Universal Print clients failing to communicate with the Universal Print service, which affects printing functions. This issue occurs when you turn on Web Proxy Auto Discovery (WPAD).
• It also adds to the Windows Kernel Vulnerable Driver Blocklist file (DriverSiPolicy.p7b) drivers at risk for Bring Your Own Vulnerable Driver (BYOVD) attacks.

Redmond also reminded customers today that Home and Pro editions of Windows 11 22H2 will reach the end of servicing (EOS) on October 8.

Until then, these editions will only receive security updates and will not receive non-security preview updates. However, Microsoft will continue supporting Enterprise and Education editions even after October.

"To continue receiving security and non-security updates after October 8, 2024, we recommend that you update to the latest version of Windows," said the company.

The latest release, Windows 11 23H2 (the Windows 11 2023 Update), was released on October 31 as an enablement package after rolling out in September as a Release Preview Insider build for enterprise testing.

It entered broad deployment on July 18 and is now available to all seekers on eligible systems. Since February, Redmond has been force-installing the Windows 11 23H2 feature update on eligible systems that have reached or were close to their end-of-service date.