package nvidia-prime 0.8.2 failed to install/upgrade: package nvidia-prime is already installed and configured

[guillaume sion]

can't install steam
change the driver from x org to nvidia 370 for the 960m
muss start ubuntu with nouveau.modeset=0
can't choose x org again

ProblemType: Package
DistroRelease: Ubuntu 16.04
Package: nvidia-prime 0.8.2
ProcVersionSignature: Ubuntu 4.4.0-45.66-generic 4.4.21
Uname: Linux 4.4.0-45-generic x86_64
ApportVersion: 2.20.1-0ubuntu2.1
AptdaemonVersion: 1.1.1+bzr982-0ubuntu14
Architecture: amd64
CrashReports:
 600:109:116:0:2016-10-28 18:26:27.926326557 +0200:2016-10-28 18:26:27.926326557 +0200:/var/crash/bbswitch-dkms.0.uploaded
 644:0:116:0:2016-10-28 18:26:24.958266732 +0200:2016-10-28 18:26:24.958266732 +0200:/var/crash/bbswitch-dkms.0.upload
 640:0:116:3455954:2016-10-28 18:26:23.326254367 +0200:2016-10-28 18:26:24.958266732 +0200:/var/crash/bbswitch-dkms.0.crash
 600:0:116:744320:2016-10-28 18:25:55.237920284 +0200:2016-10-28 18:25:56.237920284 +0200:/var/crash/nvidia-prime.0.crash
Date: Fri Oct 28 18:25:57 2016
ErrorMessage: package nvidia-prime is already installed and configured
InstallationDate: Installed on 2016-10-01 (27 days ago)
InstallationMedia: Ubuntu 16.04.1 LTS "Xenial Xerus" - Release amd64 (20160719)
RelatedPackageVersions:
 dpkg 1.18.4ubuntu1.1
 apt 1.2.12~ubuntu16.04.1
SourcePackage: dpkg
Title: package nvidia-prime 0.8.2 failed to install/upgrade: package nvidia-prime is already installed and configured
UpgradeStatus: No upgrade log present (probably fresh install)