Microsoft breaks dual-boot Windows and Linux PCs with security update sent to wrong systems

Acer Swift Edge running Linux
Dual-boot devices running Windows and Linux may not be able to boot after a mistake made by Microsoft. (Image credit: Future)

What you need to know

  • Some dual-boot devices running Windows and Linux are unable to boot after a recent update from Microsoft.
  • The security update fixed a two-year-old vulnerability in GRUB, which is an open source boot loader used on many Linux devices.
  • The update was not supposed to ship to dual-boot systems, but it was sent out to them, seemingly by accident.
  • Affected devices are unable to boot and show an error message stating, "something has gone seriously wrong."

As the saying goes, two is better than one. That's the case in many areas, and for some people, it's true for operating systems on a computer. Dual booting Windows and Linux is relatively common, but those who have PCs that dual boot may run into an issue at the moment. Due to a mistake by Microsoft, dual-boot systems are unable to boot and show an error message that reads "something has gone seriously wrong."

That error message appeared last week on affected systems after Microsoft's monthly security update rolled out. The update fixed a vulnerability in GRUB, which is an open source boot loader used on many Linux systems. That issue was two years old when fixed, and it's not clear why it took so long to address. The update was not supposed to be sent out to dual-boot systems running Windows and Linux, but it did ship to those machines, seemingly by mistake.

“The SBAT value is not applied to dual-boot systems that boot both Windows and Linux and should not affect these systems,” said a Microsoft security bulletin (the link to that bulletin no longer appears to work). “You might find that older Linux distribution ISOs will not boot. If this occurs, work with your Linux vendor to get an update.”

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The following error message appears on affected systems:

"Verifying shim SBAT data failed: Security Policy Violation. Something has gone seriously wrong: SBAT self-check failed: Security Policy Violation."

Many took to the web to highlight the issue, including creating threads on Reddit and in forums about Ubuntu and Linux Mint. It appears that several Linux distributions are affected, including Debian, Linux Mint, Puppy Linux, Ubuntu, and Zorin OS. Ars Technica reported on the issue and provided further context.

Microsoft has not confirmed the cause of the issue. Ars Technica notes that you can work around the issue by deleting the SBAT that was shipped on Tuesday, August 13, 2024. Doing so requires disabling secure boot temporarily but then reenabling it after deleting the SBAT.

Sean Endicott
News Writer and apps editor

Sean Endicott is a tech journalist at Windows Central, specializing in Windows, Microsoft software, AI, and PCs. He's covered major launches, from Windows 10 and 11 to the rise of AI tools like ChatGPT. Sean's journey began with the Lumia 740, leading to strong ties with app developers. Outside writing, he coaches American football, utilizing Microsoft services to manage his team. He studied broadcast journalism at Nottingham Trent University and is active on X @SeanEndicott_ and Threads @sean_endicott_. 

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