Windows PCs are experiencing a notable trend of multiple reboots during the installation of monthly cumulative updates, a phenomenon that has been particularly prevalent since April. The primary culprit appears to be the updates related to Secure Boot certificates, alongside necessary firmware updates that accompany these changes.
Microsoft has confirmed that it is in the process of rolling out the Secure Boot certificate update to millions of devices running Windows 11 and Windows 10. For users who have yet to receive these new certificates, the updates are likely on the horizon, barring any significant firmware limitations that might impede the process.
In previous communications, Microsoft indicated that multiple reboots might occur as part of the Secure Boot certificate rollout, especially when updates are delivered alongside cumulative updates. The August 2026 Patch Tuesday update, released on the 12th of the month, addressed approximately 400 security vulnerabilities, underscoring the importance of timely updates.
Microsoft has also emphasized the necessity of not delaying updates beyond three days, as doing so could expose users to potential AI-driven security threats. The August 2026 Update is particularly significant, as it activates the Low Latency Profile (LLP) for app launches and enhances the display of file sizes in File Explorer’s Details view. Additionally, it includes a Secure Boot certificate update for a broader range of devices, with Microsoft noting:
“This update includes additional high confidence device targeting data, increasing coverage of devices eligible to automatically receive new Secure Boot certificates.”
This note has appeared in recent cumulative updates for Windows 11, indicating that the Secure Boot update is still being actively deployed. Reports suggest that devices previously lacking the Secure Boot 2023 certificate have successfully received it following the August 2026 Update. Microsoft reassured users that certificate deployment via Windows updates will continue across supported PCs and non-managed business devices in the coming months.
Why is Windows rebooting multiple times for a Secure Boot certificate update?
<pDuring a recent Ask Me Anything session, Microsoft addressed the issue of multiple reboots occurring during the Secure Boot certificate update process. The company clarified that several reboots are necessary to complete the update of the certificates. Once the updates are fully applied, users should no longer experience this repetitive reboot cycle.
The rationale behind the multiple reboots lies in the complexity of updating Secure Boot certificates, which involves writing changes directly into the firmware. This process requires several steps: staging the changes, applying the updated certificates, and booting the PC using the newly signed bootloader. Users may notice one reboot while the Secure Boot changes are staged, another as the firmware applies the updates, and a final reboot as Windows utilizes the new bootloader.
Microsoft noted that, in most automated scenarios, these reboots are not particularly noticeable to users, as they typically occur early in the boot process. However, it is important to recognize that Secure Boot changes are not the sole reason for additional reboots. The certificate update itself modifies the firmware, and Windows Update may also deliver separate firmware updates. Consequently, if users encounter further reboots later in the same update cycle or during subsequent cumulative updates, these may stem from pending firmware or driver updates rather than a repeat application of the Secure Boot certificate.
This understanding sheds light on why some PCs seem to reboot multiple times across different monthly updates, even though Microsoft maintains that the certificate update is a singular process. The interplay of Secure Boot updates and other firmware or driver updates can lead to a more complex reboot experience for users.
