I have an Intel NUC NUC8I7HNK which I have installed Ubuntu on. If I reboot the system and then reboot it again everything is fine. Reboots without problem.
However, if I let the system sit for a few days (I don't have an exact time period) and then I try to reboot it will hang.
This could be related to grub as I believe before I made the following changes it may not have had this reboot problem:
GRUB_CMDLINE_LINUX_DEFAULT="quiet splash noacpi acpi=off"
to
GRUB_CMDLINE_LINUX_DEFAULT="acpi=ht irqpoll quiet splash"
Without making that change all the CPU cores on the machine weren't seen so I'm trying to preserve that.
Any ideas on where to look to start to resolve the problem?