Windows 7 users may want to alter their setting on their systems with an Asus motherboard as Microsoft’s Windows 7 KB133977 update conflicts with UEFI’s secure boot function, hence refusing OS boot up.
The Secure Boot option was introduced as a native feature in Windows 8 which takes advantage of the system UEFI so that it can check system integrity during its boot process. The security system protects from Malware attacks. Asus motherboards this secure feature from the UEFI’s end by default. As a result, once the Windows 7 is updated, the system detects inconsistency in OS loader keys, resulting in an inability to boot.
The problems came up since Microsoft changed its priority of its security update from the usual default ‘Optional‘ setting to ‘Recommended‘. As a result, the K133977 update gets installed automatically resulting the system getting bricked.
The step involves changing the OS type on the Secure Boot option to Other Windows and then unloading the Platform Key State after rebooting the system. Asus has outlined a step to go around the issue at hand and can be found here. So far, there have been no reports about this update affecting motherboards from other brands or any prebuilt systems, but those who are using motherboards with UEFI and Windows 7 should check the settings to be on the safe side.
You may think switching back to optional may look be a good idea for some people, there’s no telling if future updates would do something similar. You’ll never know. Either way, you’ve been advised!
— Hardware BBQ (@HardwareBBQ) May 6, 2016