Linux Network Management disabled after reboot
Problem: Network Management was disabled after a reboot and no way to enabled it again via GUI on task list (it were running). The issue was caused by NetworkEnabled=false. Use an editor, kate, gedit or similar.
sudo kate /var/lib/NetworkManager/NetworkManager.state
Change the following line it back to NetworkEnabled=true
Restart the network management program
sudo service network-manager restart
It should now work fine again. For more details see the bug report