How to configure UPS to avoid data corruption when there is an unexpected power cut?

After NAS is connected to UPS with the USB cable and power cord, you can see the UPS configuration in ADM-External Device-UPS-Preference 

There are two different scenarios you can choose to configure the option:

1. Have the NAS umount the storage and terminate the services. Then power on after the power is restored.

In ADM-External Device-UPS-Preference-Method select Safe Mode.
In ADM-Settings-Hardware-Power, disable the EuP and enable the option "In the event of a power outage, enable the NAS to return to its previous state once power has been restored"

2. NAS is co-working with other devices and needs specific boot sequence, power off the NAS when there is an unexpected power cut, will manually power on NAS when power restored.

In ADM-External Device-UPS-Preference-Method select Shut down.
In ADM-Settings-Hardware-Power, disable the option "In the event of a power outage, enable the NAS to return to its previous state once power has been restored"