1791 Encryption recovery key is not configured.

Explanation

Encryption Recovery Key is the rescue method in case the primary master key is not available on any of the nodes. In case of a situation where primary master key is not available to unlock the system, then user can enter the encryption recovery key to unlock the system. In case of External Key Management methods (USB / Key Server), the primary master keys are stored external to the system, hence reattaching the USB with primary master key or connecting to the key server will help in unlocking the system. However, with the internal key management method, the keys are stored internally on the boot drive, hence if these keys are not available due to some failure scenarios then Encryption Recovery Key can be used as an rescue method.