I have a WD Duo 8TB connected to my iMac with a USB cable. Everytime I wake the iMac I get a pop-up message “Error in RAID Configuration” telling me I have configuration issues, and that I should run WD Drive Utilities. I have done this multiple times, and each time all the tests (SMART status, scanning, and complete drive test) check out OK. Anything else to check or set-up?
Re-configuration of RAID setup would be required in this concern. You can check after configuring the RAID in your Duo drives.
After taking the backup, I would recommend you to erase the drives using WD Drive Utilities and reconfigure the RAID in these drives.