Now for the kicking part. Western Digital's MyBook box runs so hot inside that the "GreenPower" 750gig harddrive failed thermally, overheated by the controller circuit. The enclosure only features passive cooling vent holes. The drive and electronics stay somewhat sealed inside, and, to put it mildly, plastic does not make a great heat conductor.
Luckily hard drives have thermal sensors to switch them off when all becomes unbearable. The funny thing is this drive switched off when under no load whatsoever. That's right. Box running in idle mode. Nop. Nothing happening.
I'm not used to getting junk from Western Digital, but there you go. Now I know how the last drive broke/melted. This one will sit without its box cover for the summer. It will also sit upright so the controller circuit can cool down. Lesson learnt.