I upgraded this system to the Mate beta 1 and was hit by this during the process.
Rebooting and rerunning apt seems to have fixed it but gave an additional warning:
W: APT had planned for dpkg to do more than it reported back (9 vs 13).
Affected packages: virtualbox-ext-pack:amd64
ProblemType: Package
DistroRelease: Ubuntu 17.10
Package: virtualbox-ext-pack 5.1.26-1
ProcVersionSignature: Ubuntu 4.12.0-12.13-generic 4.12.8
Uname: Linux 4.12.0-12-generic x86_64
ApportVersion: 2.20.7-0ubuntu1
AptOrdering: NULL: ConfigurePending
Architecture: amd64
Date: Sat Sep 2 00:39:15 2017
DpkgHistoryLog:
Start-Date: 2017-09-02 00:39:15
Requested-By: rui (1000)
DpkgTerminalLog:
Setting up virtualbox-ext-pack (5.1.26-1) ...
virtualbox-ext-pack: downloading: http://download.virtualbox.org/virtualbox/5.1.26/Oracle_VM_VirtualBox_Extension_Pack-5.1.26.vbox-extpack
The file will be downloaded into /usr/share/virtualbox-ext-pack
dpkg: error processing package virtualbox-ext-pack (--configure):
subprocess installed post-installation script returned error exit status 8
ErrorMessage: subprocess installed post-installation script returned error exit status 8
InstallationDate: Installed on 2017-02-20 (193 days ago)
InstallationMedia: Ubuntu-MATE 17.04 "Zesty Zapus" - Alpha amd64 (20170125)
PackageArchitecture: all
Python3Details: /usr/bin/python3.6, Python 3.6.2, python3-minimal, 3.6.1-0ubuntu3
PythonDetails: /usr/bin/python2.7, Python 2.7.13, python-minimal, 2.7.13-2
RelatedPackageVersions:
dpkg 1.18.24ubuntu1
apt 1.5~rc1~ubuntu1
SourcePackage: virtualbox-ext-pack
Title: package virtualbox-ext-pack 5.1.26-1 failed to install/upgrade: subprocess installed post-installation script returned error exit status 8
UpgradeStatus: Upgraded to artful on 2017-09-02 (0 days ago)
Not sure what happened, there aren't enough info to debug it