I tried to update my system from 12.04 to 14.04 but it dosen't work. So I started under "Systen Tools -->Systemverwaltung -->Rechner-Hausmeister the tool to "clean" my sytem....but it dosen't also work. I'm sure that I updated my system into the past and I haven't installed external sources.

[Reiner Plonka]

see summary

to 1)
Ubuntu 12.04.5 LTS
to 2)
via terminal: N: Paket pkgname kann nicht gefunden werden
via system: ubuntu 12.04 LTS
Prozessor: Intel® Core™ i7 CPU 860 @ 2.80GHz × 8
Grafik: VESA: JUNIPER
Typ des Betriebssystemes: 64 Bit
to 3)
I' would like to update my system directly without formatting my hard disk

ProblemType: Bug
DistroRelease: Ubuntu 12.04
Package: update-manager 1:0.156.14.17
ProcVersionSignature: Ubuntu 3.2.0-67.101-generic 3.2.60
Uname: Linux 3.2.0-67-generic x86_64
NonfreeKernelModules: fglrx
ApportVersion: 2.0.1-0ubuntu17.6
Architecture: amd64
Date: Mon Aug 18 22:58:36 2014
EcryptfsInUse: Yes
GsettingsChanges:
 com.ubuntu.update-manager first-run false
 com.ubuntu.update-manager launch-time 1408392460
 com.ubuntu.update-manager show-details true
 com.ubuntu.update-manager window-height 502
 com.ubuntu.update-manager window-width 600
InstallationMedia: Ubuntu 10.04 LTS "Lucid Lynx" - Release amd64 (20100429)
MarkForUpload: True
PackageArchitecture: all
ProcEnviron:
 TERM=xterm
 PATH=(custom, no user)
 LANG=de_DE.UTF-8
 SHELL=/bin/bash
SourcePackage: update-manager
Symptom: ubuntu-release-upgrader-core
UpgradeStatus: Upgraded to precise on 2014-08-18 (0 days ago)
VarLogDistupgradeTermlog: