I tried enabling BitLocker on my C: drive, and before I got to any BitLocker setup, a window appeared that said Windows Recovery Environment was being moved, and "You will no longer be able to use Windows Recovery Environment unless it is manually enabled and moved to the system drive." It was the warning from Scenario 1 Step 5 of this article: Scenario 1: Turning On BitLocker Drive Encryption on an Operating System Drive (Windows 7) I ended up not encrypting my drive with BitLocker, and found that my system partition is 199 MB. So, how do I "manually enable" Windows Recovery Environment and "move it to the system drive"?