WD My Book Duo 16TB - Degraded RAID - Which Drive?

Product: WD My Book Duo 16TB
RAID: 1 (Mirrored)
Filesystem: APFS (Apple File System)

Problem:
Red Light blinking indicating error. Found status message of “Degraded RAID” by using “WD Drive Utilities” (MacOS). Apperantly on of two drives needs to be replaced (RMA).
But when checking on the drive with “WD Drive Utilities” (MacOS) i says both drive are “Online”.

Question:
How can I check which of the two drives is the one that has failed?
(How do I know which one to send back regarding RMA?)

Thank you in advance for any help

Hi Chechin,

You should try contacting WD’s Technical Support about this for live assistance and troubleshooting

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