macOS Sierra (10.12.2) + My Book Duo 12TB

Bought a 12TB drive and set up a RAID 1 configuration to use as a mirrored (2x6TB) backup on my Mac with Time Machine. Initial backup went well then drive 2 failed a week later telling me the drive was damaged. WD replaced the drive and I set up again, backed up successfully again and now, 3 weeks later am getting the same error - telling me the RAID configuration has failed. Cannot reformat the drive(s).

What are the KNOWN issues with OS X Sierra and My Book Duo?

It seems unlikely that the drive would fail twice without there being a known issue and now I’m thinking of buying a drive from a different manufacturer as I cannot afford to go through this another time.

Hello,

I recommend you contact WD support for assistance with this.

https://support.wdc.com/support/case.aspx?lang=en