While changing the motherboard battery yesterday (Friday), most cables were disconnected
and then later re-connected. That included the hard drive connection to the motherboard.
I also disconnected and reconnected both the power cable and the data cable where they
plug in to the hard drive itself. The hard drive was removed, vacuumed, and put back into
its place.
No problems since, but I haven't done a "dnf upgrade" since then.
thanks,
Bill.