A device, method, and system for switching library managers of a data library while maintaining data library storage devices online. A library manager accepts and executes data transaction commands for access to data residing on the storage devices of the data library. A transition manager module receives a directive to transition library management functions from a first library manager to a second library manager. The transition manager module stops the first library manager from accepting new data transaction commands while maintaining the storage devices online. The first library manager may execute previously accepted data transaction commands. The transition manager module suspends the library management functions of the first library manager and activates the library management functions of the second library manager. The storage devices of the data library may complete data transaction commands throughout the library manager transition.