As it turns out, the recently released KB5012170 update causes many inconveniences for customers. Besides the need to update UEFI to install the Secure Boot DBX update, KB5012170 messes with BitLocker, causing numerous computers to boot into BitLocker recovery after applying the update.
According to The Register (via Bleeping Computer) and many reports on Microsoft Forums, Reddit, and Twitter, Windows 11 asks customers to enter the recovery key on the BitLocker recovery screen. Fortunately, the bug does not affect the stored data, which means users can regain access to the system by entering their keys stored in Microsoft Accounts or Active Directory. Those unfamiliar with the procedure can check out the official documentation describing how to locate the BitLocker recovery key.
Another annoying bug users report after installing KB5012170 is disk configurations changing from RAID to AHCI. Luckily, like with the BitLocker recovery bug, users can safely switch the affected systems back to RAID without losing any data. Still, many are upset that another botched update caused IT admins and regular users to waste their time and efforts on fixing what should not be broken.
As customers try to hide their pain, Microsoft is yet to confirm the new bug in KB5012170. For now, the only acknowledged issue in this release is the Security update for Secure Boot DBX failing to install without a UEFI update on select systems.