Basically, BitLocker Drive Preparation tool prepares a hard drive with the partitions necessary for BitLocker Drive Encryption. Most installations of Windows 7 or later recognize the command-line tool. Here is how you can use it.

Using BitLocker Drive Preparation Tool via Command Prompt in Windows

  1. In order to use BitLocker Drive Preparation command-line tool, open the administrative Command Prompt.
  2. Next, you can use the following command with suitable descriptors mentioned below and press Enter: The above-mentioned command is in general form and its variable parameters can be altered using the following descriptors: This displays the drive letter, the total size, the maximum free space, and the partition characteristics. Only valid partitions are listed. Unallocated space is not listed if four primary or extended partitions already exist- Example: To display information for C: drive, use bdehdcfg –driveinfo C: command. Prepares a partition for use as a system drive by BitLocker and Windows Recovery. By default, this partition is created without a drive letter- Example: In order to use this command to designate an existing drive (K) as the system drive, use bdehdcfg -target K: merge at Command Prompt. Assigns a new drive letter to the portion of a drive used as the system drive. As a best practice, it is recommended that you do not assign a drive letter to your system drive- Example: Using command bdehdcfg -target default -newdriveletter K: illustrates that default drive is being assigned the drive letter K. Specifies the size of the system partition when a new system drive is being created. The default is 300 MB in minimum size is 100 MB- Example: Use command bdehdcfg -target default -size 500 to allocate 500 MB to the default system drive. Informs the BitLocker Drive Preparation Tool that all actions and errors are not to be displayed in the command-line interface- Example : bdehdcfg -target default -quiet Use this to restart BitLocker Drive Preparation Tool after an operation is completed- Example: BdeHdCfg.exe -target d: merge -quiet -restart In this way, you can use the BitLocker Drive Preparation command-line tool. Interested readers may visit TechNet and KB933246 to find out further possibilities. See this post if you receive BitLocker Drive Encryption cannot be used because critical BitLocker system files are missing or corrupted (0x8031004A) error. Related reads: