Back in August 2024, Microsoft released an update for various versions of Windows including Windows 10 and 11 that broke dual-booting with Linux on some setups. They've now finally solved it. Only took them 9 months.
The issue came from a Windows security update, something that was not supposed to affect systems where it detected a dual-boot but Microsoft failed on that causing problems for many to be unable to boot into their Linux installs.
From Microsoft:
After installing the August 2024 Windows security update, (KB5041160) or the August 2024 preview update, you might face issues with booting Linux if you have enabled the dual-boot setup for Windows and Linux in your device. Resulting from this issue, your device might fail to boot Linux and show the error message “Verifying shim SBAT data failed: Security Policy Violation. Something has gone seriously wrong: SBAT self-check failed: Security Policy Violation.”
The August 2024 Windows security and preview updates apply a Secure Boot Advanced Targeting (SBAT) setting to devices that run Windows to block old, vulnerable boot managers. This SBAT update will not be applied to devices where dual booting is detected. On some devices, the dual-boot detection did not detect some customized methods of dual-booting and applied the SBAT value when it should not have been applied.
Microsoft did tweak this so that from September 19, 2024 and later updates did not do this automatically, but the damage was already done.
As of the May 13, 2025 update for Windows, this has now been solved. As the changelog notes:
Article taken from GamingOnLinux.com.
- [Secure Boot Advanced Targeting (SBAT) and Linux Extensible Firmware Interface (EFI)] This update applies improvements to SBAT for the detection of Linux systems.
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