Microsoft has made a bizarre tweak to an update for Windows 7 that can prevent some systems from booting. The Windows 7 update KB3133977 was switched from 'Optional' to 'Recommended' and Microsoft knew ahead of time the update would cause problems for some users but decided to do nothing about it. The update fixes a problem that stops BitLocker encrypting drives because of service crashes in svhost.exe. The update only causes a problem with ASUS motherboards. Microsoft says, "After you install update 3133977 on a Windows 7 x64-based system that includes an ASUS-based main board, the system does not start, and it generates a Secure Boot error on the ASUS BIOS screen. This problem occurs because ASUS allowed the main board to enable the Secure Boot process even though Windows 7 does not support this feature." The update wasn't causing many issues while it was optional. But now that it's recommended, more users have downloaded the update, and more users have experienced problems with the update. ASUS has provided a solution to the problem. Microsoft has also provided a solution, but you might not like it. Their solution in a nutshell: update to Windows 10.