Save Candidate Configurations
at the top right of the web interface to create a snapshot file (.snapshot.xml) of the candidate configuration or to overwrite the existing snapshot with your latest changes. If the firewall reboots before you commit your changes, you can then revert the candidate configuration to the current snapshot to restore changes you made between the last commit and the last snapshot. To revert to the snapshot, select
Device > Setup > Operations
Revert to last saved configuration. If you don’t revert to the snapshot after a reboot, the candidate configuration will be the same as the last committed configuration (the running configuration).