Microsoft has begun rolling out the Secure Boot 2023 certificate update for eligible Windows 11 and Windows 10 PCs ahead of the expiration of the original certificates on June 24, 2026. The update includes additional device targeting data to increase coverage for automatic updates. Devices receive the new certificates after demonstrating successful update signals. The original Secure Boot certificates were issued in 2011, with expiration dates set for June 24, 2026, June 27, 2026, and October 19, 2026. Microsoft has been distributing replacement 2023 certificates since 2024, with the June 2026 update expanding eligible devices significantly. Users can check their Secure Boot status through the Windows Security app or System Information. If a PC did not receive the update, it will still function normally but may not receive future boot-level security updates. Multiple restarts after updates are expected behavior, and the SecureBoot folder in Windows is not malware. Windows 10 users in the Extended Security Updates program are also receiving the Secure Boot update. The expiration of the Microsoft Corporation KEK CA 2011 on June 24 means no new Secure Boot revocation payloads can be signed with the old key, but existing signed payloads will continue to function.