Summary

  • Dual-boot Windows and Linux users should avoid new Windows updates for now.
  • A recent Windows update causes the error when accessing the Linux partition.
  • An SBAT setting is the culprit of the issue - use Reddit solutions or use the opt-out registry key.

If you're using a dual-boot PC with Windows and Linux, you may want to hold off on the newest Windows update. Reports began trickling in stating that people who used a Windows and Linux dual boot setup encountered a strange error message while trying to access the Linux partition. Now, Microsoft has broken the silence and stated that, yes, a recent Windows update has broken things, and the culprit is a Secure Boot Advanced Targeting (SBAT) setting.

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The newest Windows update causes chaos for Linux dual-boot systems

As stated on the Microsoft Learn website, it seems that the August 2024 security update has flipped a switch that is causing a really nasty issue:

After installing the August 2024 Windows security update, released August 13, 2024 (KB5041585), 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.”

Fortunately, this setting only activates if you're dual-booting. If you only have one operating system installed on your PC, then SBAT won't cause you any trouble.

It doesn't seem that Microsoft has an easy way to fix this issue. The only advice it suggests is to not install the update, or use a special opt-out registry key listed in the article to prevent it from finalizing. Fortunately, the kind folk over at the LinuxQuestions subreddit have been hard at work helping people out with this error, so give their solutions a try if you've been hit with this nasty error. And if you're not using the Linux partition anymore, check out our guide on how to remove Linux from a dual boot.