nm-applet regularly crashes at logon, in combination with failing 3G connection

[gerardo]

I'm running Ubuntu 15.10 with network-manager 1.0.4-0ubuntu5.2.

Regularly (if not always) the nm-applet icon is not showing in the Unity panel after logon. Syslog shows these error messages:

Jan 23 21:07:21 desk1 gnome-session[3904]: (nm-applet:4812): nm-applet-WARNING **: Could not find ShellVersion property on org.gnome.Shell after 5 tries
Jan 24 09:42:37 desk1 gnome-session[19922]: (nm-applet:20700): libnm-glib-WARNING **: Error in get_property: Method "Get" with signature "ss" on interface "org.freedesktop.DBus.Properties" doesn't exist
Jan 24 09:42:38 desk1 gnome-session[19922]: (nm-applet:20700): nm-applet-WARNING **: Cannot grab information for modem at /org/freedesktop/ModemManager1/Modem/0: No ModemManager support
Jan 24 09:42:38 desk1 gnome-session[19922]: (nm-applet:20700): nm-applet-WARNING **: ModemManager is not available for modem at /org/freedesktop/ModemManager1/Modem/0
Jan 24 09:42:38 desk1 gnome-session[19922]: message repeated 3 times: [ (nm-applet:20700): nm-applet-WARNING **: ModemManager is not available for modem at /org/freedesktop/ModemManager1/Modem/0]
Jan 24 09:42:38 desk1 gnome-session[19922]: nm-applet:ERROR:applet-device-broadband.c:644:get_icon: assertion failed: (info)

Manually starting nm-applet from a Terminal works, sometimes however only after some attempts where error messages similar to the ones above are shown (btw, even when succeeding, the first 2 warning/error messages on the ss signature and the ShellVersion show up). Once nm-applet is started, the 3G modem connection signal bars are shown and sometimes indeed a network connection (through 3G modem) is available. Often however, several manual disconnect and subsequent connect operations are needed before having the network connection really up and running.

I suspect hence that there is an issue with my ModemManager and/or NetworkManager configuration or implementation, and that nm-applet is not robust enough to properly deal with these connection failures.

I have no issues on another Ubuntu 15.10 system with the same version of network-manager installed.

[gerardo (geestbos)]

Please let me know which information is needed to allow bug fixing.

[Launchpad Janitor (janitor)]

Status changed to 'Confirmed' because the bug affects multiple users.

[Andre (andrei-b-taru)]

What seemed to work for me is to modify the NetworkManager systemd service (/lib/systemd/system/NetworkManager.service) and add "ModemManager.service" to the "After" list:

After=network-pre.target dbus.service ModemManager.service

[gerardo (geestbos)]

Meanwhile, on Ubuntu 16.04 and with network-manager 1.2.2-0ubuntu0.16.04.3, from my side I have no longer the described issues. Both ModemManager, NetworkManager and nm-applet are working flawlessly.