May I ask if your 6TB Red Pro had this issue from the beginning or was the noise something it developed after a time? Was your replacement drive a refurbished drive from WD or did you get a new replacement?
Here is another thread for a 4TB Red Pro that may exhibit the same behavior: https://community.wd.com/t/wd-red-pro-4-tb-constant-noise-when-idle/180213
It is a real bummer that these drives have this idle noise, as otherwise it is shaping up to be the perfect drive for my needs.
