Can't Shutdown, Reboot, or Logout (Ubuntu 16.04). Recent Install

HI,

After a recent install of Ubuntu 16.04, my system is not able to Shutdown, Reboot, or Logout with a hang. When ruing everything works as expected.

During a Shutdown, Reboot, or Logout out there is message displayed that says "NMI watchdog: BUG: soft lockup - CPU5 stuck for 22s! [plymounthd]. This the cpu number changes from time to time. There is also message that the about a stall on a cpu.

Occasionally, the system will Shutdown, Reboot, or Logout without issue, but this is very rare.

I have to hold down the power button until the system shuts off in all cases.

Any help would be greatly appreciated.

System:
Dell Inspiron 15 7000 model 7579
16GB RAM
480GB SSD - holds '/', '/boot', '/boot/efi', and swap
960GB SSD - holds '/home'

Thanks,
Robert