There are many factors due to which RAID based NAS can fail. Though it is always advised to take the help from RAID Data Recovery experts in case of power failures, overheating, virus attack, incorrect setup, OS errors, and hardware controller failures, you can follow the steps mentioned below otherwise.
· Power off the RAID NAS.
· Remove all hard drives and connect all NAS RAID drives to Windows PC.
· Install and run recovery software.