Windows server provides the ability to encrypt the volumes using Bit locker functionality. Backup Exec supports the Backup and Restore of Bitlocker enabled volume limitations.
Following is the list of scenarios where Bitlocker is enabled on specific resources and how Backup Exec works:
Backup of System Drive and Data drive with Bitlocker enabled on both drives
If the system being backed up is rebooted then every time you must logon to the target system so that Backup Exec does not display the warning message.
Unlike system drive, for data drive with bitlocker enabled, Backup Exec displays a warning message to manually unlock the data drive or skip the drive from backup, even if you are logged into the system. Every time the data drive has to be manually unlocked, else the scheduled job fails.
Backup Exec behaviour for restoring volumes
For File/Volume level restore, similar behavior is observed. You must unlock the restore destination and if you select a backup file/Volume data, unlock the destination volume manually, else Backup Exec displays a warning or skips the data during restore.
Solution:
You must unlock the destination volumes by performing the following steps:

It is recommended that you use Windows built-in, auto-unlock functionality. This is not applicable to a system drive. When you reboot a system, you must logon using the Recovery password.