Comment 0 for bug 555571

Network Manager worked in the beginning after patching and rebooting the KNetworkManager showed "Network Management disabled". No option to enable it again was available.

The issue was caused by
  NetworkingEnabled=false
in
 /var/lib/NetworkManager/NetworkManager.state

After changing it back to
 NetworkingEnabled=true
in
 /var/lib/NetworkManager/NetworkManager.state
and running
 sudo service network-manager restart
everything worked fine again.

Full content of /var/lib/NetworkManager/NetworkManager.state

[main]
NetworkingEnabled=true
WirelessEnabled=true
WWANEnabled=true

root@ltdar2:/etc/NetworkManager# lsb_release -rd
Description: Ubuntu lucid (development branch)
Release: 10.04

network-manager:
  Installed: 0.8-0ubuntu2
  Candidate: 0.8-0ubuntu2
  Version table:
 *** 0.8-0ubuntu2 0
        500 http://ch.archive.ubuntu.com/ubuntu/ lucid/main Packages
        100 /var/lib/dpkg/status

ProblemType: Bug
DistroRelease: Ubuntu 10.04
Package: network-manager 0.8-0ubuntu2
ProcVersionSignature: Ubuntu 2.6.32-19.28-generic 2.6.32.10+drm33.1
Uname: Linux 2.6.32-19-generic x86_64
Architecture: amd64
CRDA: Error: [Errno 2] No such file or directory
Date: Mon Apr 5 09:48:24 2010
EcryptfsInUse: Yes
Gconf:

InstallationMedia: Error: [Errno 13] Permission denied: '/var/log/installer/media-info'
IpRoute:
 192.168.1.0/24 dev wlan0 proto kernel scope link src 192.168.1.44 metric 2
 169.254.0.0/16 dev wlan0 scope link metric 1000
 default via 192.168.1.1 dev wlan0 proto static
Keyfiles: Error: [Errno 2] No such file or directory
ProcEnviron:
 LANGUAGE=
 LANG=en_US.UTF-8
 SHELL=/bin/bash
SourcePackage: network-manager