How to detect, suspend, and re-enable BitLocker during a Task Sequence

In this blog post, I am going to show some simple steps that you can add to your Task Sequences to be able to detect, disable, and enable BitLocker status. This can be useful (and necessary) when performing activities like flashing the BIOS, running the new MBR2GPT utility, or upgrading to a newer version of Windows. In Configuration Manager, there are a few Task Sequence steps that are for BitLocker configuration and management:

Disable BitLocker – this step will disable BitLocker encryption on the current operating system drive or one that you specify and runs in a full operating system (does not run in WinPE). It does not decrypt the drive, but it does leave the key protectors visible in clear text on the hard drive. This step only disables BitLocker for one reboot (if you would like to see this step updated, vote for my Configuration Manager Uservoice item Add Reboot Count functionality to the Disable BitLocker TS Step). This means that BitLocker will be enabled again after the restart. If you need BitLocker to be disabled for more than one restart, then you can use manage-bde with a Run Command Line step (see below). Also, if there are data drives encrypted, then they need to be disabled before disabling the operating system drive.

Note: before running MBR2GPT, BitLocker should be disabled. Also, for just a Windows 10 In-place Upgrade with BitLocker (not doing MBR2GPT), it is not required to disable BitLocker, however, there have been reports of BitLocker not being suspended long enough during the upgrade (see the link to Jonathan Conway’s blog below) .

Enable BitLocker – this step will enable BitLocker encryption on a drive. It only runs in a full operating system (in other words, it does not run in WinPE). If selected for use, the TPM must already be enabled, activated, and allow ownership prior to running this step. This step can be used to re-enable BitLocker if the drive is already encrypted with BitLocker but in a disabled state.

Pre-provision BitLocker – this step runs under WinPE (only) and is used to enable BitLocker during the WinPE phase of the Task Sequence. It also encrypts the used drive space, which makes encryption times faster. Once in the full operating system, use the Enable BitLocker step to apply the key management options. This step is generally be used in New Computer or Wipe-and-Load Task Sequences.

Manage-bde – this is a built in command line tool that allows for the enabling, disabling, updating and reporting on BitLocker. The Microsoft TechNet documentation on Manage-bde is a bit stale and has not been updated to reflect some of the new capabilities that have been added in the newer releases. The most important one is the ability to control the reboot count when the protectors have been suspended. There is a new parameter called -RebootCount or -rc that takes a value between 0 and 15, where 0 suspends the protection indefinitely. This can be useful if you have several reboots during a Task Sequence and you need to make sure that BitLocker stays suspended (optional method listed below).

Note: Jonathan Conway has a great blog on how to use Manage-bde with the Task Sequence called SCCM Windows 10 Upgrade Task Sequence: BitLocker PIN Protector Issues on Laptops.

Now, to disable BitLocker, you could place that step in the Task Sequence and allow it to ‘Continue on error’. If you like to only use ‘Continue on error’ in certain cases and definitely want to know if BitLocker was enabled (so that you can conditionally re-enable it later on in the Task Sequence), then this can easily be done with a Set Task Sequence Variable step. Create a new Group called Disable BitLocker and on the Options tab add the following:
Task Sequence Variable _SMSTSinWinPE equals “False”

Place a Set Task Sequence Variable step in the Disable BitLocker Group and call it Set OSDBitLockerStatus for the name. Enter OSDBitLockerStatus for the Task Sequence Variable and enter Protected for the Value.
On the Options tab, add the following:
WMI Namespace: root\cimv2\Security\MicrosoftVolumeEncryption
WMI Query: select * from win32_encryptablevolume where driveletter = ‘c:’ and protectionstatus = ‘1’

This will check the BitLocker status on the C: drive (which is hopefully the OS drive). Keep in mind that if there are other data volumes that are BitLocker encrypted, these will need to be detected and decrypted first. Those systems can be filtered out in the collection targeting or it can be built into the Task Sequence using the same logic as above.

Next, add a Disable BitLocker step (with the option set Current operating system drive).
On the Options tab, add the following:
Task Sequence Variable OSDBitLockerStatus equals “Protected”

Optionally (recommended if needing multiple reboots), instead of using the built in Disable BitLocker step, add a Run Command Line step:
Name: Disable BitLocker
Command line: manage-bde -protectors -disable C: -RC 0
On the Options tab, add the following:
Task Sequence Variable OSDBitLockerStatus equals “Protected”

 

To re-enable BitLocker later on in the Task Sequence, create another group called Re-enable BitLocker.
On the Options tab, add the following:
Task Sequence Variable _SMSTSinWinPE equals “False”
Task Sequence Variable OSDBitLockerStatus equals “Protected”

Next, add an Enable BitLocker step under the Re-enable BitLocker Group (with the option set Current operating system drive). Since the drive is already encrypted, this step will just re-enable the key protectors if they are currently disabled (like if you used managed-bde and specified a reboot count).

Remember that the built in Disable BitLocker step will only disable BitLocker for one reboot (similar to what happens when you suspend BitLocker from the Control Panel applet), but if you used manage-bde with -RC 0, you will need to re-enable BitLocker.

Keep this Task Sequence template handy so that you can easily copy and paste into other Task Sequences in the future. I will be referring to this template in upcoming blog posts.

Originally posted on https://miketerrill.net/

One thought on “How to detect, suspend, and re-enable BitLocker during a Task Sequence

  1. Pingback: Upgrading the BIOS Part 2 | Mike's Tech Blog

Leave a Reply

Fill in your details below or click an icon to log in:

WordPress.com Logo

You are commenting using your WordPress.com account. Log Out / Change )

Twitter picture

You are commenting using your Twitter account. Log Out / Change )

Facebook photo

You are commenting using your Facebook account. Log Out / Change )

Google+ photo

You are commenting using your Google+ account. Log Out / Change )

Connecting to %s