Bitlocker not auto-unlocking C: drive on server 2008 R2

Question

Here's the scenario. We'got a Dell PE T110 (I know, I know), that we've enabled Bitlocker via TPM. On reboots, it asks to re-enter the bitlocker key, and we have no idea why it's not auto-unlocking. On the drive that's supposed to auto-unlock, we have the OEM parition, RECOVERY (with system,active,primary), and the OS (boot,pagefile,crash dump,primary partition) (Bitlocker encrypted). I've been reading that the OS needs to be the active partition for the autounlock to function. If not, any ideas where I should look next?

Answer 1

I've been reading that the OS needs to be the active partition for the autounlock to function

That isn't accurate.

This can be due to the recovery key being regenerated but not saved to TPM. By far the most likely cause is the C: drive not being first in the boot order. The next most likely cause is something in the hardware/firmware changed, which would basically mean it needs to be redone.

Here is a sample of what the manage-bde diskmgmt output should look like:

C:\>manage-bde -status
BitLocker Drive Encryption: Configuration Tool version 6.1.7601
Copyright (C) Microsoft Corporation. All rights reserved.

Disk volumes that can be protected with
BitLocker Drive Encryption:
Volume C: [OSDisk]
[OS Volume]

    Size:                 232.56 GB
    BitLocker Version:    Windows 7
    Conversion Status:    Fully Encrypted
    Percentage Encrypted: 100%
    Encryption Method:    AES 128 with Diffuser
    Protection Status:    Protection On
    Lock Status:          Unlocked
    Identification Field: Some description
    Key Protectors:
        Numerical Password
        TPM

Suffice it to say if there is not a TPM protector listed, the drive was not encrypted correctly/as you expected.