This may not be a hardware failure. I have several Western Digital Drives. All have reported drive failure within the last month. They include My Book Duo (12 TB) - 2 of them, My Passport (4 TB) - 2 of them, My Passport Ultra (3 TB), and My Passport Ultra (2 TB).
The 2TB Passport Ultra was configured as a Time Machine drive attached to Airport Extreme.
The 4TB Passports were configured via Disk Utility as a Raid 1 pair and connected through a Duo.
Both 12TB Duos were configured as Raid 1 drives, directly connected to iMac (A1297). One of the Duos is only 2 weeks old. The other is currently going to WD for exchange.
In all raid cases, WD Utilities reported the pair as degraded with one of the platters dead (empty slot in the Duo).
Time Machine simply stopped making the 3TB available for use.
It makes me wonder if there is a software compatibility issue here, not a hardware problem. I can erase and rebuild each drive when connected to the iMac. It’s always WD Utilities that reports a raid configuration problem.
have you tried reinstalling the software to see if you get the same issues on the drives? Also what happens if you connect the drives to a different computer.
I have downloaded and reinstalled WD Utilities 3 times. WD Utilities says drive 2 is empty. And this is the 3rd 12TB Duo in 6 months to say that. Disk Utility only sees 6TB, too. I will try connecting it to another computer this evening.
FWIW, I am running Sierra beta at the moment, but the problem seems to go back several stable releases.
I have now had a chance to connect the Duo to my MacBook Pro and to try a different cable (another WD cable is all I have with the USB-B connector). I connected it before installing WD Utilities and again after installing. In all cases, the Duo drive showed the same error state (red slow flash power, red drive #2).
Perhaps I bail out of the beta MacOS program and wait for the next stable release?
No. I am out of the MacOS Beta program. I have a replacement Duo in the box that I haven’t been brave enough to connect. The other Duo does not function on OS 10.12.6 stable release. I can pull the platters and both test fine. In the enclosure, though, it still shows drive 2 empty.