Event ID 24591 — BitLocker Startup

Applies To: Windows Server 2008

When a computer protected with BitLocker Drive Encryption is restarted, the early startup components perform a series of integrity checks and, if the system passes, attempts to retrieve the needed key information to unlock any BitLocker-protected volumes. Success depends on the availability of configured key protectors, such as the TPM or a user-supplied PIN, and the existence of volume metadata stored within the encrypted drive.

If Windows cannot unlock the Windows operating system volume, BitLocker enters recovery mode. If the user can supply a recovery password or insert a USB flash drive with a recovery key, BitLocker will unlock the volume.

After the Windows operating system volume has been successfully unlocked, BitLocker uses encrypted information stored in the volume metadata and Windows registry to unlock any data volumes configured for automatic unlocking.

Event Details

Product: Windows Operating System
ID: 24591
Source: Microsoft-Windows-BitLocker-Driver
Version: 6.0
Message: Auto-unlocking failed for volume %2.


Manually unlock a volume

BitLocker supports the ability to automatically unlock data volumes after Windows has started. If the volume cannot be automatically unlocked, you can unlock the volume manually, and, if desired, re-enable the auto-unlock feature.

To perform these procedures, you must have membership in Administrators, or you must have been delegated the appropriate authority.

Manually unlock a volume

To manually unlock a volume:

  1. Click Start, and then click Control Panel.
  2. Click Security.
  3. Click BitLocker Drive Encryption.
  4. If the User Account Control dialog box appears, verify the proposed action is correct, and then click Continue.
  5. Click Unlock for the desired volume.
  6. Provide the appropriate key or password to unlock the volume.
  7. Close the BitLocker Drive Encryption window.

Enable auto-unlock for a volume

To enable auto-unlock for a volume:

  1. Open an elevated Command Prompt window. Click Start, point to All Programs, click Accessories, right-click Command Prompt, and then click Run as administrator.
  2. Type cscript manage-bde.wsf -autounlock -enable e: where e: is the drive letter for the volume to be automatically unlocked at startup.


To verify that BitLocker has started successfully:

  1. If the computer is not running, start the computer.
  2. If BitLocker has been configured to use a USB flash drive, insert the USB flash drive. If BitLocker has been configured to use a PIN, enter your PIN when prompted.
  3. Verify that Windows Welcome Screen, Logon Screen or Desktop appears. This indicates that BitLocker has correctly unlocked the Windows operating system volume.
  4. Log on to Windows and access any data volumes that are encrypted with BitLocker.

Note: Data volumes can be configured to be automatically unlocked or to require manual unlocking.

BitLocker Startup

Core Security