Microsoft’s recent security patch has caused widespread disruption for users running dual-boot systems with both Windows and Linux. The update, designed to fix a long-standing vulnerability in the GRUB boot loader used by Linux devices, has instead created boot issues, preventing some Linux installs from functioning correctly.

Unexpected Consequences of the Patch

The security patch, released last week, was aimed at addressing a two-year-old vulnerability in Secure Boot—a critical technology that protects devices from malicious software during the boot process. Although Microsoft intended the update to avoid dual-boot systems, the patch has inadvertently affected them, leaving many Linux users facing “security policy violation” messages and errors stating, “something has gone seriously wrong.”

Wide Impact Across Linux Distributions

Linux distributions including Ubuntu, Debian, Linux Mint, Zorin OS, and Puppy Linux are among those hit by the update. Reports from Ars Technica and user forums across Reddit and Ubuntu have highlighted the scope of the problem, with numerous users expressing frustration over the inability to boot into their Linux systems after applying the update.

Secure Boot and the Vulnerability Patch

Microsoft’s update was meant to improve the Secure Boot framework by blocking vulnerable Linux boot loaders that could potentially affect Windows security. However, despite assurances that the patch wouldn’t target dual-boot systems, the unexpected issue has taken many by surprise. Secure Boot is widely used in both Windows and Linux to prevent unauthorized firmware from running during system startup, making it a crucial part of system security.

Possible Workaround for Linux Users

Microsoft has yet to issue an official response to the problem, but there is a workaround for Ubuntu users. It involves disabling Secure Boot at the BIOS level, which allows users to bypass the issue temporarily. By disabling Secure Boot and removing Microsoft’s SBAT policy from the terminal, affected users can regain access to their Linux installations.

Ongoing Secure Boot Challenges

While Secure Boot has been a fundamental part of Windows security for years, especially with its mandatory inclusion in Windows 11, this latest mishap highlights its vulnerabilities. In recent years, researchers have discovered numerous flaws in Secure Boot, with some findings even indicating that the technology is broken on many PCs.

For more details on how this update is affecting dual-boot systems, check the full report here.