an error message that reads "Something has gone seriously wrong." Microsoft has investigated the issue and released a statement.

GRUB is a popular bootloader (a program that boots up operating systems) for Linux. Two years ago, a vulnerability was found in GRUB that lets threat actors bypass Secure Boot and install malware on the system level. It's this vulnerability that Microsoft tried to patch with the recent update titled Secure Boot Advanced Targeting (or SBAT).

It was only supposed to target Windows-only devices, and Microsoft warned that some older Linux installations might be affected. The patch description reads, "The SBAT value is not applied to dual-boot systems that boot both Windows and Linux and should not affect these systems. You might find that older Linux distribution ISOs will not boot. If this occurs, work with your Linux vendor to get an update." But according to Ars Technica, this update was installed on Windows devices dual-booting with new releases of Debian, Ubuntu, Linux Mint, and others. Booting from ISO files loaded on bootable drives is failing too.

After the reports poured in, Microsoft released a statement addressing the issue. "This update is not applied when a Linux boot option is detected. We are aware that some secondary boot scenarios are causing issues for some customers, including when using outdated Linux loaders with vulnerable code. We are working with our Linux partners to investigate and address it," Microsoft said. The company is maintaining that dual-booting devices were never affected, except the ones running older versions of GRUB.

Dual-booting issues are common because Windows updates and features often break them. But people have figured out a way to mitigate the problem even without guidance from Microsoft. Temporarily disabling Secure Boot and deleting the Microsoft patch using a terminal command within Linux reportedly fixes the booting issue.

Source: Ars Technica