When installing monthly Windows 11 updates, users typically expect their devices to restart only once. However, recently, some users have experienced their devices restarting twice or even multiple times when installing large updates, including the July 2026 update. Microsoft explained that this is due to the deployment of new version security boot certificates. Typically, Windows monthly updates require only a single restart, but recently, Microsoft has been rolling out 2023 version security boot certificates to replace the old 2011 version certificates that are set to expire in June 2026. To complete the certificate deployment, the system needs to perform an additional certificate update process beyond the regular update, triggering an extra restart. Microsoft emphasized that this is a one-time operation. Once the device completes the deployment of the new certificate, subsequent updates will return to the normal single-restart process. Additionally, the July 2026 update has caused issues such as unexpected shutdowns, performance degradation, overheating, and rapid battery drain on some Dell computers. Microsoft has released an emergency update, KB5121767, to replace the problematic update and recommends that affected Dell computer users install this update, while other users can skip it.