Microsoft has announced that certain Secure Boot certificates used by Windows systems will begin expiring from June 2026.

To maintain compatibility with future Windows security updates and Secure Boot protections, affected systems may require updated Secure Boot certificates and BIOS updates.

What is happening?

Starting June 2026, certain older Secure Boot security certificates (dating back to 2011) used by Windows will expire.

Secure Boot is a built-in security feature on your computer. Every time you turn on your PC, it acts like a security guard, checking your Windows software's digital "ID badge" (certificate) to ensure it is authentic and has not been altered by malicious software. To keep this protection active and compatible with future updates, these certificates must be renewed.

What does this mean for me?

• No Boot Interruptions: The expiration of these certificates will NOT prevent your computer from starting or functioning normally.
• Security Risk: If your system does not receive the required updates, it will miss out on future Secure Boot security enhancements and protections from Microsoft.

Which Windows versions are affected?

The update applies to all currently supported versions of Microsoft Windows that receive official security updates. Specifically, this includes:

• Windows 11: All retail and business versions (such as versions 22H2, 23H2, and 24H2). These systems will automatically receive the new certificates through regular monthly Windows Updates.
• Windows 10 (Specific Editions): Only specialized editions that are still officially supported by Microsoft, such as Enterprise LTSC (Long-Term Servicing Channel) or systems enrolled in the Extended Security Updates (ESU) program.

What do I need to do?

To ensure your system remains fully protected and compatible, you do not need to check model numbers or parts lists.
The rule is simple: always keep both Windows and your system BIOS fully updated.

• Install all Windows Updates: Keep Windows Update enabled. Microsoft distributes the required certificate updates automatically through its regular update cycles. 
• Install the latest BIOS update: Every BIOS update currently available on the official Dynabook Support Website, as well as those delivered through Windows Update, already includes the new Secure Boot certificates. 

Simply download and install the latest available BIOS and Windows updates for your device.
If your system is already running the newest version, you are completely covered and no further action is required.

Additional Support

For more details regarding Microsoft's certificate transition, please refer to official Microsoft Support Article KB5036210.
https://support.microsoft.com/en-us/topic/windows-secure-boot-certificate-expiration-and-ca-updates-7ff40d33-95dc-4c3c-8725-a9b95457578e