Comment 12 for bug 1316634

Next steps:
 - 1) Check the file /var/lib/NetworkManager/NetworkManager.state when the problem occurs next time.

With connected network it looks like:

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

 - 2) Check the files in /var/lib/NetworkManager/ for their contents. Probably this might help to track down the problem.