A key retrieval system includes a management system and a managed system that is coupled to the management system through a network. The managed system includes a managed device, a management system configuration storage, a remote access controller device that stores a management system configuration for the management system in the management system configuration storage and provides a key management client subsystem that is configured to use the management system configuration to access the management system. The managed system also includes a BIOS. The BIOS detects an event that triggers unlocking the managed device. The BIOS determines that the remote access controller device is unavailable and, in response, retrieves the management system configuration and accesses the management system using the management system configuration. The BIOS then retrieves the locking key from the management system and unlocks the managed device using the locking key.