Booted into the Windows 8 recovery menu to see if I could decrypt my secondary HDD with the recovery tools. Found that I can do it in the dos prompt there after unlocking the drive.
However, after typing this:
X:\>manage-bde -off C:
The output can be found below. There is NO indication of how long its going to take:
BitLocker Drive Encryption: Configuration Tool version 6.2.9200
Copyright (C) 2012 Microsoft Corporation. All rights reserved.
Decryption is now in progress.
X:\Sources>
Did I miscalculate? Should it be showing me the decryption progress? Or is this expected and should I go back to bed and do it's thing until tomorrow (it's an SSD)?