System won't power off

[Tom]

Since I clean installed Ubuntu 16.04 LTS my system won't power off anymore on itself, I have to hold the powerbutton.

Ubuntu 15.04 and 15.10 had no problems turning off my system.

ProblemType: Bug
DistroRelease: Ubuntu 16.04
Package: systemd 229-4ubuntu4
ProcVersionSignature: Ubuntu 4.4.0-21.37-generic 4.4.6
Uname: Linux 4.4.0-21-generic x86_64
NonfreeKernelModules: nvidia_uvm nvidia_modeset nvidia
ApportVersion: 2.20.1-0ubuntu2
Architecture: amd64
Date: Sat Apr 23 21:46:35 2016
ExecutablePath: /lib/systemd/systemd
InstallationDate: Installed on 2016-04-23 (0 days ago)
InstallationMedia: Ubuntu 16.04 LTS "Xenial Xerus" - Release amd64 (20160420.1)
MachineType: Hewlett-Packard HP Z420 Workstation
ProcEnviron:
 TERM=linux
 PATH=(custom, no user)
ProcKernelCmdLine: BOOT_IMAGE=/vmlinuz-4.4.0-21-generic.efi.signed root=/dev/mapper/ubuntu--vg-root ro
SourcePackage: systemd
SystemdDelta:
 [EXTENDED] /etc/systemd/system/display-manager.service → /lib/systemd/system/display-manager.service.d/xdiagnose.conf
 [EXTENDED] /lib/systemd/system/rc-local.service → /lib/systemd/system/rc-local.service.d/debian.conf
 [EXTENDED] /lib/systemd/system/systemd-timesyncd.service → /lib/systemd/system/systemd-timesyncd.service.d/disable-with-time-daemon.conf

 3 overridden configuration files found.
UpgradeStatus: No upgrade log present (probably fresh install)
dmi.bios.date: 05/27/2015
dmi.bios.vendor: Hewlett-Packard
dmi.bios.version: J61 v03.88
dmi.board.name: 1589
dmi.board.vendor: Hewlett-Packard
dmi.board.version: 0.00
dmi.chassis.type: 6
dmi.chassis.vendor: Hewlett-Packard
dmi.modalias: dmi:bvnHewlett-Packard:bvrJ61v03.88:bd05/27/2015:svnHewlett-Packard:pnHPZ420Workstation:pvr:rvnHewlett-Packard:rn1589:rvr0.00:cvnHewlett-Packard:ct6:cvr:
dmi.product.name: HP Z420 Workstation
dmi.sys.vendor: Hewlett-Packard

[Tom (tomhek)]

There are a couple of errors about one of the memory modules in this system not being okay. That module was replaced by HP but the problem still exists.

Might be related to bug #1464917