New Windows 10 update breaks dual boot with Linux

Microsoft has released a new update for Windows 10 which fixes some security flaws in the most recent version of the operating system. Although these downloads fix some vulnerabilities, installing them causes problems that may drive some people crazy. The latest version is for those who have a dual boot Linux computer.

update KB5044273available for Windows 10 builds 19044.5011 and 19045.5011, is now available through Windows Update. The file description on Microsoft’s support website mentions that the patch addresses security issues and includes quality improvements across all supported editions of Windows 10 version 22H2.

The download also includes a servicing stack update that creates chaos if you have a dual boot computer with Windows 10 and Linux. The Known Issues section reports the following:

“After installing this security update, you may experience problems booting Linux if your device has dual boot settings enabled for both Windows and Linux.

As a result of this issue, your device may be unable to boot into Linux and display a message: Shin SBAT data verification error: security policy violation. Something went wrong: SBAT self-test failed – security policy violation“

This issue has been around since mid-August and can be resolved by adding an entry to the Windows registry or disabling Secure Boot in your computer’s BIOS.

How to restore dual boot in Windows 10

According to Microsoft, the security update is August 2024. applied the Secure Boot Advanced Targeting (SBAT) parameter. This was done to block some vulnerabilities in older boot managers. Although the patch included a detector that could not be installed on dual boot computers, it did enforce SBAT by default on some computers using special methods.

If you installed an update and lost dual boot or simply can’t start Windows, you can follow these steps.

• If you can’t boot into Windows, simply disable Secure Boot. inside your BIOS. To do this, press the key DEL or F2 when starting the computer and accessing the Boot (BOOT) partition. Find the Secure Boot option and disable it.
• If you can run Windows and have lost dual boot you will need to uninstall the latest update or run the following script
  • Click the Windows Start button, type CMD to run Command Prompt as Administrator.
  • Write the following line: reg add HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Control\SecureBoot\SBAT /v OptOut /d 1 /t REG_DWORD
  • Restart your computer

As with other failures, Windows is working on a permanent fix for this error.. It goes without saying that this only happens in some specific cases, but it is worth knowing the problem and possible solutions.