Comment 7 for bug 1011073

I'm affected by this too. It seems to happen intermittently without any obvious connection to anything else. I most often notice it more or less directly following a resume from suspend, though that may be a coincidence since that's also the time when I most often want to manually connect to my VPN, having just opened my laptop at a place away from home.

Another symptom when the bug occurs: The nm-indicator does not react to clicks on any of the items. While it may list some Wifi networks as well as 3G connections and the "Enable …" checkboxes, clicking any of them simply does nothing. Wifi networks can't be changed, 3G connections can't be brought up, networking can't be disabled. It's as if the indicator has lost partial connectivity to the network-manager proper.

Other network-manager interfaces continue to work, both nmcli/nm-tool and "System Settings → Network" list all available connections and can bring them up.

Looking through the network-manager bugs on launchpad at least #1012154 and #1000948 seem to be duplicates of this. (I'm commenting here since so far this is the most active one.)