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Event ID 24601 — BitLocker Startup

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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: 24601
Source: Microsoft-Windows-BitLocker-Driver
Version: 6.0
Symbolic Name: FVE_KEYRING_TPM_INVALID_PCR
Message: The PCRs did not match during restart.

Resolve

Check any system change and re-enable BitLocker

BitLocker entered recovery, and a user has successfully completed the recovery process by using a recovery key (stored on a USB flash drive) or a recovery password (entered manually at the recovery screen). BitLocker entered recovery because the configuration of the computer has unexpectedly changed.

This change could represent a deliberate attack or an unauthorized attempt to access data, or it could represent a change made deliberately by an administrator while BitLocker was enabled.

Check that any changes to the early startup components or Windows system files were authorized. Once you have verified that the system has not been compromised, re-enable BitLocker to reset the configuration information.

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

To disable and re-enable BitLocker:

  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 Turn off BitLocker.
  6. Click Disable BitLocker.
  7. In the BitLocker Drive Encryption window, click Turn On BitLocker.
  8. Close the BitLocker Drive Encryption window.

Verify

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