I do not know if this is a mechanical failure of the disks,
Not failure, exactly. I think that the grease in the spindle bearings is so stiff that the disks do not spin up to their rated speed in a short enough time to avoid timing out, so the bootup fails.
I can state from personal experience that my 18GB Mark2 will start up reliably at temperatures below zero Fahrenheit, and that it will not start up at minus 15 degrees Fahrenheit.
I do not make a habit of this, but a few times, due to forgetfulness on my part I have tested this.
tanstaafl.
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