Unencrypted partition – partition with non-locked file system, without BitLocker Drive Encryption (BDE) applied to it, or after turning BitLocker off.
BDE partition – partition with data encrypted with BDE
Locked partition – BDE-partition, access to FS of which is locked.
Unlocked partition – BDE partition, access to which was unlocked by one of used keys.
For BDE partitions, all Non-FS-Destructive operations (which change something on partition sectors level) are prohibited.
Such partitions can be backed up (without preserving encryption) and restored in non-encrypted (Unlocked) state.
Also, you can copy BDE partition or disk with BDE partitions, preserving all keys and encryption methods that were used on Source drive.
Locked partition cannot be selected for copy or backup.
If the disk contains at least one locked partition, this disk cannot be selected for copy or backup.
Trying to perform forced copy of locked partition (for example – when using script and having the partition in Locked state prior to scheduling the script), 0x10093 error will pop up.
To make Locked partition Unlocked or Unencrypted, open Windows Explorer, go to My Computer (or This Computer), then right-click on the disk and select Manage BitLocker.
Suspend protection: Locked partition will become Unlocked partition
Turn off BitLocker: BDE partition (either Locked or Unlocked) will become Unencrypted partition
You can always re-enable BitLocker by selecting Turn on BitLocker later.
Advanced instructions for managing BitLocker are available here: docs.microsoft.com