When I shutdown my Windows 10 PC via menu, this is the sequence of events that occur typically:
- Windows pops up a message that the system will be shut down. Disk (I still have a RAID with spinning platters) is busy.
- The screen goes into power-save mode while the disks are still busy (I have a "disk LED" that shows controller activity).
- Eventually I hear the sound of disks spinning down ("disk LED" goes off, too), and the power LED goes off.
- After about 5 seconds more I see the USB power to "collapse", i.e. the lights on any USB devices go off.
- Then I power off the PC by mains switch.
However after booting I see it rather frequently that Windows takes a long time to boot, also saying that the last shutdown was unexpected (see https://superuser.com/a/1293346/964771). I don't understand why: The disks were turned off, the PC-power was off, how can Windows record anything after disks an CPU were powered down? Or is it that the shutdown sequence actually failed before powering down?
I also have the impression that waiting maybe another 5 to 10 seconds after step 4 before doing step 5 does not produce that message.