I bought an 8TB WD easystore external HD which has (and yes pretty much everyone knows this) a red drive EFAX (WDC WD80EFAX-68LHPN0). I ran the short and extended tests on HD sentinel and everything was fine.   Now when i left it attached to my server which has stablebit scanner, i received an email stating" One or more disks are damaged and have data on them that is unreadable: WD easystore 25FB USB Device - 344 KB unreadable (688 sectors) - The rest of the disk is still being scanned Mod