Microsoft solves dual-boot problems with Windows and Linux

Microsoft released Windows updates last August. After installing them, many dual-boot configurations and Linux boot media no longer started. Microsoft had tried to block old boot managers. The problem should now be solved.

Microsoft discusses the problem in the Windows Release Health Notes. The August 2024 update and preview version added a Secure Boot Advanced Targeting (SBAT) setting on devices running Windows to block old, vulnerable boot managers. Users with a dual boot installation with Linux and Windows could experience problems as a result. When starting Linux, the error message "Verifying shim SBAT data failed: Security Policy Violation. Something has gone seriously wrong: SBAT self-check failed: Security Policy Violation".

Update should not take place with dual boot

The SBAT update should not take place if a dual-boot configuration has been detected. However, the detection often failed. This resulted in the observed error. Microsoft no longer distributed this SBAT update with the September updates, so only the August updates can trigger the problem. Microsoft now writes that the problem has been fixed with the Windows security updates from the May patchday.

However, Microsoft remains silent as to what the solution now looks like. The description suggests that the SBAT updates are taking place again, but that the dual-boot detection has been improved – but this is not confirmed. Various Windows versions are affected. For example, Windows Server 2022, 2019, 2016, 2012 R2 and 2012 as well as the desktop systems Windows 11 23H2, 22H2 and 21H2 and Windows 10 22H2, 21H2 and Enterprise 2015 LTSB.

In August, Microsoft also provided information on how to prevent the SBAT update by creating registry keys, for example. The Redmond-based company also explained how dual-boot systems can be restored.

(dmk)