Microsoft Enterprise Platforms Support: Windows Server Core Team
My name is Tanner Slayton and I am a Sr. Support Escalation Engineer for Microsoft on the Windows Core Team. I am writing today to shed some light on a common Bitlocker problem that we see.
* While you can accomplish most tasks via the Bitlocker Control Panel Applet, I am going to be using the manage-bde commands from an elevated command prompt.
Specific operations or actions will cause Bitlocker to go into Recovery Mode and ask you to enter the 48-digit Recovery Key. This can be caused by several things, and a complete list can be viewed here , but today I am going to go over the most common issues.
Scenario # 1: When you are using a Laptop or Desktop computer and do not have the BIOS Boot order with the OS HDD listed as the first boot device. The reason for this is the boot device makes up part of the system measurement used by Bitlocker and this must remain consistent to validate the system status and unlock BitLocker. (I.e. if you have the DVD-ROM drive listed first and had a bootable media inserted, this can cause the system measurement to change.) Some firmware will also treat PXE network boot as a change in boot order – even when the user does not choose network boot. Changing from a wireless to wired network can trigger a recovery event. Putting the HDD first in boot order generally eliminates these issues.
o Suspend Bitlocker drive encryption by typing "manage-bde -protectors -disable c:” from an elevated command prompt.
o Go into the BIOS and change the Boot Order so the OS HDD is first in the list.
o By default from most hardware vendors, the HDD is not the first boot device.
o If you have a laptop with a docking station, make sure that it is plugged into the docking station, in order to make sure that the external devices presented by the docking station are present in BIOS.
o Boot into the Operating System and run "manage-bde -protectors -enable c:"
Scenario # 2: When you are either deploying a new system or encrypting the drive for the first time. You might pause the Bitlocker encryption process, in order to speed up the performance or while performing other tasks, so that encryption can run later or you need more than the 6 GB worth of free space to continue deploying the system. When you run "manage-bde -pause c:" you are pausing the drive encryption of C:, but not the Bitlocker protectors on the system.
You might say to yourself, if I run "manage-bde -status c:" I see that the protection is off on that drive. The reason you see this is that the protection for the drive is not yet completed, but the clear text key still exists.
Volume C:  [OS Volume] Size: 37.17 GB BitLocker Version: Windows 7 Conversion Status: Encryption Paused Percentage Encrypted: 3% Encryption Method: AES 128 with Diffuser Protection Status: Protection Off <--- Where it shows "Protection Off" Lock Status: Unlocked Identification Field: None
o When you need to pause the encryption, whether for performance or drive space reasons, you need to run "manage-bde -pause c:"
o After encryption has been paused, you will want to run "manage-bde -protectors -disable c:"
o Once you have completed your tasks and wish to start the encryption process again you can run "manage-bde -resume c:"
o Once the encryption is complete, or if you have completed your tasks, you will then want to run "manage-bde -protectors -enable c:"
Scenario # 3: The BIOS / TPM firmware are out of date on the systems.
o Suspend Bitlocker drive encryption “manage-bde –protectors –disable c:”
o Update the BIOS on the system
o If there is a TPM Firmware update, please follow the vendor installation instructions.
o Reboot the Operating System and run “manage-bde –protectors –enable c:”
Scenario # 4: When you are installing additional language packs onto the system, and selecting the option to apply the language settings to all users and system accounts. This causes a locale change in the BCD (Boot Configuration Database), which Bitlocker with TPM interprets as a boot attack.
o Add language packs to the system and make any language settings.
o Resume Bitlocker drive encryption “manage-bde –protectors –enable c:”
Scenario # 5: When you create or modify any of the partitions that reside on the O/S drive.
o Shrink, expand, or create any partitions on the drive.
I want to thank you for your time today and hope that this information was helpful.
Tanner Slayton Senior Support Escalation Engineer Microsoft Enterprise Platforms Support
VERY helpful information. I would have thought Microsoft would post something similar to this. Thanks again for your work!
Hi, very good post. But these scenarios do not cover everything. What would you do in a case where bitlocker encrypts an external hard drive and stores the password on local system. And after doing that, it is unable to decrypt the external drive even when provided with right password or key? If you need more details, you can see my post here....I have had a disaster with it...and havent recovered :(
Win 7 is a breeze of fresh air ... but having these problems is like having the golden (or blue ) days back!!
Also the article shows Microsoft is very short sighted when it came to Bitlocker and how recovery mode is triggered. Some companies need to leave the PXE boot enabled as not all users can be walked through the BIOS. We dont have the budget to purchase say VPro from Intel to manage the BIOS and our machines are spread through 200+ remote sites. If the machine needs to be reimaged we also cannot afford the shipping costs to send the machine back to a config lab for reimaging. Instead we reinstall on site and leave the PXE boot enabled for just such a reason. Here is where PCR10 does not make sense, PXE boot was enabled before bitlocker was enabled. If you hibernate the machine then it sends Bitlocker into recovery mode but with PCR 10 disabled everything runs fine. Very short sighted Microsoft!!!!!
I have encrypted my D: which size is 130 GB. After installation 3days it was working properly but now it is not booting and while the booting process it is asking for Bit locker recovery file. so pls help me.
My id is email@example.com
We have been deploying bitlocker for well over a year. We do set HDD first in the bios under all boot orders but on our m91's a USB drive left in the USB port still throws a bitlocker code request, even after removing it from the boot order in the bios. Anyone run into this?
Thanks for the post, solved my problem with the first scenario.