Just solved a problem on my Fedora 12 32-bit machine (Acer Aspire One D250). For some reason, the nm-applet is not starting when I log into the desktop. When I start a terminal and fire up nm-applet as a normal user, I get the following error:

[user@machine ~]$ nm-applet

** (nm-applet:7050): WARNING **:  request_name(): Could not
 acquire the NetworkManagerUserSettings service.
  Error: (9) Connection  ":1.372" is not allowed to own the service 
"org.freedesktop.NetworkManagerUserSettings" due to security policies
in the confuguration file

But, when I substitute user as root (su -), I can start it and all’s well. Not a happy situation.

Did some checking and got a hint from – http://bbs.archlinux.org/viewtopic.php?id=63576.

So, what I have done is the following. In etc/dbus-1/system.d/nm-applet.conf, I had to add the
following for my userid:

I am using the “user” setting and not a group as suggested in the URL above as I do not want to create a non-standard group for this purpose. Suffice that my immediate problem is solved.

On the Fedora 12 machine that is experiencing this issue, policykit is as follows:

$ rpm -qa|grep polkit
polkit-0.95-0.git20090913.6.fc12.i686
polkit-gnome-0.95-0.git20090913.3.fc12.i686
polkit-desktop-policy-0.95-0.git20090913.3.fc12.noarch

On another Fedora 12 machine that all’s well policykit is as follows:

$ rpm -qa|grep polkit
polkit-0.95-0.git20090913.3.fc12.i686
polkit-gnome-0.95-0.git20090913.6.fc12.i686
polkit-desktop-policy-0.95-0.git20090913.3.fc12.noarch

Posted this to BZ 549253.