Windows 7 / Getting Started

How to Decommission a BitLocker Drive Permanently

Compromises in confidentiality can occur when computers or hard disks are decommissioned. For example, a computer that reaches the end of its usefulness at an organization might be discarded, sold, or donated to charity. The person who receives the computer might extract confidential files from the computer's hard disk. Even if the disk has been formatted, data can often be extracted.

BitLocker reduces the risks of decommissioning drives. For example, if you use a startup key or startup PIN, the contents of the volume are inaccessible without this additional information or the drive's saved recovery information.

You can decommission a drive more securely by removing all key blobs from the disk. By deleting the BitLocker keys from the volume, an attacker needs to crack the encryption-a task that is extremely unlikely to be accomplished within anyone's lifetime. As a cleanup task, you should also discard all saved recovery information, such as recovery information saved to AD DS.

To remove all key blobs on a secondary drive (data volume), you can format that drive from Windows or the Windows RE. Note that this format operation will not work on a drive that is currently in use. For example, you cannot use it to more securely decommission the drive used to run Windows.

To remove all key blobs on a running drive, you can create a script that performs the following tasks:

  1. Calls the Win32_EncryptableVolume.GetKeyProtectors method to retrieve all key protectors (KeyProtectorType 0).
  2. Creates a not-to-be-used recovery password blob (discarding the actual recovery password) by using Win32_EncryptableVolume.ProtectKeyWithNumericalPassword and a randomly generated password sequence. This is required because Win32_EncryptableVolume.DeleteKeyProtector will not remove all key protectors.
  3. Uses Win32_EncryptableVolume.DeleteKeyProtector to remove all of the usable key protectors associated with the identifiers mentioned previously.
  4. Clears the TPM by calling the Win32_TPM.Clear method.

For more information about developing a script or application to perform secure decommissioning on a BitLocker-encrypted drive, refer to the Win32_EncryptableVolume WMI provider class documentation at and the Win32_TPM WMI provider class documentation at

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In this tutorial:

  1. Managing Disks and File Systems
  2. Overview of Partitioning Disks
  3. How to Choose Between MBR or GPT
  4. Converting from MBR to GPT Disks
  5. GPT Partitions
  6. Choosing Basic or Dynamic Disks
  7. Working with Volumes
  8. How to Create a Simple Volume
  9. How to Create a Spanned Volume
  10. How to Create a Striped Volume
  11. How to Resize a Volume
  12. How to Delete a Volume
  13. How to Create and Use a Virtual Hard Disk
  14. File System Fragmentation
  15. Backup And Restore
  16. How File Backups Work
  17. File and Folder Backup Structure
  18. How System Image Backups Work
  19. How to Start a System Image Backup from the Command Line
  20. How to Restore a System Image Backup
  21. System Image Backup Structure
  22. Best Practices for Computer Backups
  23. How to Manage Backup Using Group Policy Settings
  24. Previous Versions and Shadow Copies
  25. How to Manage Shadow Copies
  26. How to Restore a File with Previous Versions
  27. How to Configure Previous Versions with Group Policy Settings
  28. Windows ReadyBoost
  29. BitLocker Drive Encryption
  30. How BitLocker Encrypts Data
  31. How BitLocker Protects Data
  32. TPM with External Key (Require Startup USB Key At Every Startup)
  33. TPM with PIN (Require PIN At Every Startup)
  34. TPM with PIN and External Key
  35. BitLocker To Go
  36. BitLocker Phases
  37. Requirements for Protecting the System Volume with BitLocker
  38. How to Enable the Use of BitLocker on the System Volume on Computers Without TPM
  39. How to Enable BitLocker Encryption on System Volumes
  40. How to Enable BitLocker Encryption on Data Volumes
  41. How to Manage BitLocker Keys on a Local Computer
  42. How to Manage BitLocker from the Command Line
  43. How to Recover Data Protected by BitLocker
  44. How to Disable or Remove BitLocker Drive Encryption
  45. How to Decommission a BitLocker Drive Permanently
  46. How to Prepare AD DS for BitLocker
  47. How to Configure a Data Recovery Agent
  48. How to Manage BitLocker with Group Policy
  49. The Costs of BitLocker
  50. Windows 7 Encrypting File System
  51. How to Export Personal Certificates
  52. How to Import Personal Certificates
  53. How to Grant Users Access to an Encrypted File
  54. Symbolic Links
  55. How to Create Symbolic Links
  56. How to Create Relative or Absolute Symbolic Links
  57. How to Create Symbolic Links to Shared Folders
  58. How to Use Hard Links
  59. Disk Quotas
  60. How to Configure Disk Quotas on a Single Computer
  61. How to Configure Disk Quotas from a Command Prompt
  62. How to Configure Disk Quotas by Using Group Policy Settings
  63. Disk Tools
  64. EFSDump
  65. SDelete
  66. Streams
  67. Sync
  68. MoveFile and PendMoves