Consider the following scenario. On a Windows Vista-based computer, you configure the BitLocker Drive Encryption feature to encrypt a volume or to decrypt a volume. Then, you restart the computer in Windows Preinstallation Environment (Windows PE) or in Windows Recovery Environment (Windows RE). In this scenario, you unexpectedly experience heavy disk activity.
This problem may occur in rare instances in which a volume has not been converted to a fully encrypted or fully decrypted state by BitLocker Drive Encryption. In this situation, BitLocker Drive Encryption may resume encryption of a volume or decryption of a volume when you restart the computer in either Windows PE or Windows RE.
To work around this problem, follow these steps:
Click Start, type cmd in the Start Search box, and then click cmd in the Programs list.
At a command prompt, type the following command, and then press ENTER: