On my Windows 8 machine, I have set up backup to a network location on my new NAS (a Synology DS412+).
Backup has succeeded. But in the "Windows 7 File Recovery" section of the Control Panel it says "The disk that your backup is saved on is about to fail":
But I have no other indication that the NAS is about to fail. Logging into the NAS, it reports that the "DiskStation is working well". The NAS is configured with RAID 6. SMART reports no errors whatsoever on any of the four disks. I have used the NAS extensively for several weeks with no issues at all.
Windows event logs of the backup show no warnings or errors.
What exactly is the basis for Windows's diagnose that the disk is "about to fail"? What has it detected?