Automatic backup features help ensure that no edits are lost is the event of power loss, computer crashes, or human error.
The Auto Backup feature can be enabled to save the previous revision of a file anytime you save a new version. This feature creates a .BAK version of the file before overwriting it allowing you to revert back to the previously saved version of a file at any time.
The Auto Save feature can be enabled to automatically save the diagram that you have open periodically at prescribed intervals so that catastrophic errors cause the loss of minimal information.