Upgrade problem from Ubuntu 14.04 to 15.04 [closed]

Question

I tried to upgrade from Ubuntu 14.04 to 15.04, but I got error:

@ubuntu14:/etc/apt$ sudo apt-get upgrade
Reading package lists... Done
Building dependency tree
Reading state information... Done
You might want to run 'apt-get -f install' to correct these.
The following packages have unmet dependencies:
 perl : Depends: perl-modules (>= 5.20.2-2ubuntu0.1) but 5.18.2-2ubuntu1.1 is installed
        Recommends: rename but it is not installed
E: Unmet dependencies. Try using -f.

Then trying "sudo apt-get -f install":

@ubuntu14:/etc/apt$ sudo apt-get -f install
Reading package lists... Done
Building dependency tree
Reading state information... Done
Correcting dependencies... Done
The following packages were automatically installed and are no longer required:
  libguice-java libidl-common libidl0 liborbit2
Use 'apt-get autoremove' to remove them.
The following extra packages will be installed:
  libalgorithm-c3-perl libcgi-fast-perl libcgi-pm-perl libclass-c3-perl
  libclass-c3-xs-perl libcpan-meta-perl libdata-optlist-perl
  libdata-section-perl libfcgi-perl libmodule-build-perl
  libmodule-signature-perl libmro-compat-perl libpackage-constants-perl
  libparams-util-perl libpod-readme-perl libregexp-common-perl
  libsoftware-license-perl libsub-exporter-perl libsub-install-perl
  libtext-template-perl perl-modules
Suggested packages:
  libb-lint-perl libcpanplus-dist-build-perl libcpanplus-perl
  libfile-checktree-perl liblog-message-perl libobject-accessor-perl
The following NEW packages will be installed:
  libalgorithm-c3-perl libcgi-fast-perl libcgi-pm-perl libclass-c3-perl
  libclass-c3-xs-perl libcpan-meta-perl libdata-optlist-perl
  libdata-section-perl libfcgi-perl libmodule-build-perl
  libmodule-signature-perl libmro-compat-perl libpackage-constants-perl
  libparams-util-perl libpod-readme-perl libregexp-common-perl
  libsoftware-license-perl libsub-exporter-perl libsub-install-perl
  libtext-template-perl
The following packages will be upgraded:
  perl-modules
1 upgraded, 20 newly installed, 0 to remove and 208 not upgraded.
23 not fully installed or removed.
Need to get 0 B/3,585 kB of archives.
After this operation, 2,588 kB of additional disk space will be used.
Do you want to continue? [Y/n]
Setting up util-linux (2.25.2-4ubuntu3) ...
insserv: Service mountdevsubfs has to be enabled to start service hwclock
insserv: exiting now!
update-rc.d: error: insserv rejected the script header
dpkg: error processing package util-linux (--configure):
 subprocess installed post-installation script returned error exit status 1
Errors were encountered while processing:
 util-linux
E: Sub-process /usr/bin/dpkg returned an error code (1)

cat /etc/lsb-release

ubuntu14:/etc/apt$ cat /etc/lsb-release
DISTRIB_ID=Ubuntu
DISTRIB_RELEASE=15.04
DISTRIB_CODENAME=vivid
DISTRIB_DESCRIPTION="Ubuntu 15.04"

Any idea how to fix?

Answer 1

Solved by downloading Ubuntu Server 16.04 ISO, and installed over the old bad Ubuntu installation.

Did not format /dev/sda1 system partition, reassigned as root partition, so I kept the /home/user content, did not lose them. I had to recreate the /etc/fstab, because it got overwritten.

So I saved almost all data, except the settings in /etc and earlier installed packages, which had to be installed again.

I hope this solution helps others with similar problems.