Antivirus : ERROR: Database load killed by signal 9 ERROR: Failed to load new database
f updating Antiviurs definition fails with error "ERROR: Database load killed by signal 9" or "ERROR: Failed to load new database", this is caused by the specification of the memory in the NAS, which is not big enough to extract the growing size of the Antivirus definition nowadays.
To work around this, you could disable ALL applications in the App Center and reboot the NAS to free up some memory for use. Once booted up, run updating Antiviurs definition again and it should complete the update successfully.