I'm using external USB hard drives to backup my server (Windows Server Backup). These drives are encrypted by Bitlocker To Go. I configured the disks to get unlocked automatically, because they are swapped every Friday by an employee.

However, Windows Server won't unlock them until someone logs on to the server, causing the backup to fail:

The backup operation attempted at '2015‎-‎11‎-‎11T23:00:11.671366800Z' has failed to start, error code '2155348147' (The backup destination is not accessible because it is locked by Bitlocker Drive Encryption.).

How can I get my backup drives unlocked without user interaction?


"Configured to get unlocked automatically" probably means you stored the password in a Windows user's Credential Store. This is not available to the system unless the Credential Store is unlocked. What you can do is use manage-bde.exe to unlock the drive from a Task Scheduler action.

  • I've been using a Powershell script with hardcoded passwords to unlock the drives. This is a weak workaround, but suitable for our security concept. Might post it as an answer. – Physikbuddha Mar 29 '16 at 10:03

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