In this post, you’ll learn more about the Error FVE_E_CANNOT_SET_FVEK_ENCRYPTED – 0x8031002D that is returned when working with the COM-based APIs in Win32
Win32 COM Error
FVE_E_CANNOT_SET_FVEK_ENCRYPTED – 0x8031002D
Win32 COM Error Error Description
The drive encryption algorithm and key cannot be set on a previously encrypted drive. To encrypt this drive with BitLocker Drive Encryption, remove the previous encryption and then turn on BitLocker.