Windows 10/11 and Linux Dual-Boot Users Advised Not to Install Latest Update to Prevent Boot Issues

Users who run Windows 10/11 alongside Linux in a dual-boot setup are advised against installing the latest cumulative update, following a warning from a netizen @R🥬 on Landian.news. This recent update introduces a known issue that prevents the system from booting properly after installation.

Error on Boot:

Verifiying shim SBAT data failed: Security Policy Violation.Something has gone seriously wrong: SBAT self-check failed: Security Policy Violation.

The problem affects all supported versions of Windows 10/11. Microsoft identified this issue in July and has yet to resolve it, thus including a note in the cumulative update's list of known issues.

Root of the Problem:

The crux of the issue lies in the Secure Boot Advanced Targeting (SBAT) and the Linux Extensible Firmware Interface (UEFI). The cumulative update applies SBAT to the Windows system, blocking the vulnerable Linux EFI (Shim boot loader) from running, which in turn prevents the Linux system from booting correctly.

However, this problem doesn't universally occur. According to Microsoft, older Linux ISO images might fail to boot, and users encountering this issue should contact their Linux distributor for the latest ISO image.

Temporary Solutions:

For users who have already installed the update and are unable to boot into their Linux system, restarting and entering the BIOS settings to disable Secure Boot can provide a temporary fix, allowing system access.

Alternatively, if you can access the Windows system, attempting to uninstall the corresponding update is another solution. Below are the specific versions and patch numbers for this update:

• Windows 11 23H2: KB5041585
• Windows 11 22H2: KB5041585
• Windows 11 21H2: KB5041592
• Windows 10 22H2: KB5041580
• Windows 10 21H2: KB5041580
• Windows 10 LTSC 2021: KB5041580
• Windows 10 LTSC 2019: KB5041578
• Windows 10 LTSB 2016: KB5041773
• Windows 10 LTSB 2015: KB5041782

Given the potential for significant disruption, users with dual-boot systems are strongly encouraged to delay this particular update until a permanent fix is made available.