Question: High Sierra has bricked 2 HDDs, now what?
I was using a USB3 HDD to act as my local files space for my cloud backup. Upgrading to High Sierra went smoothly until the HDD stopped being recognised. This varied from the finder telling 'disk type not recognised, please initialise' to Disk Utility not seeing the drive at all (the drive clicks and whirs so gets power).
I though OK, let's cut my losses so bought the exact same drive (Seagate Expansion Portable Drive 1TB). Arrived loaded with the default software. Did what I always do i.e. erase with Disk Utility. Did that, at which point the disk unmounted and is as dead and invisible to Disk Utility as the first one. ***?
MacBook Pro with Retina display, macOS High Sierra (10.13.1), i5 - 16/1024