Microsoft has released an update for the Surface 2 that fixes a problem reported by some users early after the two weeks of launch.

The bug is related to the BitLocker built into Windows RT 8.1, in which “Surface 2 prompts you for the BitLocker recovery key when you restart the device” or restore from the sleep mode.

The bug occurs on Surface 2 with new firmware, and for some inexplicable reason, Windows RT 8.1 detects some problem in the configuration (maybe some hardware malfunction or exceeded failed login attempts, although Microsoft didn’t provide details) and locks down the device.

Initially, BitLocker was introduced with Windows Vista, and the team of Terry Myerson has been updating with the successors, Windows 7 and Windows 8/8.1. It’s a full disk encryption feature that uses the AES encryption algorithm in CBC mode with a 128-bit or 256-bit key, to protect the data stored on your computer or tablet. It’s a useful feature business consumers, and also supported by server platforms.

At power on, restart, or to resume from sleep, the operating system calls for the inclusion of the recovery key. For some inexplicable reason (Microsoft did not provide details) Windows RT 8.1 detects a problem in the configuration (or a hardware malfunction or an excessive number of failed login attempts), and then turns on the device locks.

If you don’t remember the recovery key then just go to and sign in with Microsoft account that you used on your Surface 2.

FYI, the problem isn’t concerned with the Surface RT, Surface Pro and Surface Pro 2. Next week, Microsoft is planning to release a new firmware for the Surface Pro 2 on the Patch Tuesday, which will also resolve the problems that occurred with the update of December 2013.