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When I try to use the software center, the authentication windows pops up and disappears after 1 second shaking sideways (like when the password is incorrect) even though I was not able to type anything.

I can use synaptic and type my password, but if I try to change groups or user accounts the same issue happens: authentication window pops up for 1 second and disappears. Any ideas on what can be wrong? It was working good til today.

This is the out put of /var/log/auth.log:

May 15 20:46:46 laura-G31D-M9 polkitd(authority=local): Operator of unix-session:/org/freedesktop/ConsoleKit/Session13 FAILED to authenticate to gain authorization for action org.debian.apt.install-or-remove-packages for system-bus-name::1.356 [/usr/bin/python /usr/bin/software-center] (owned by unix-user:laura)
May 15 20:46:49 laura-G31D-M9 dbus-daemon: [system] Rejected send message, 1 matched rules; type="method_call", sender=":1.356" (uid=1000 pid=17053 comm="/usr/bin/python) interface="org.freedesktop.DBus.Introspectable" member="Introspect" error name="(unset)" requested_reply=0 destination=":1.303" (uid=0 pid=15565 comm="/usr/bin/python))

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Did you try to enable a fingerprint reader or enable any other kind of login / authentication method? – K. Hendrik May 15 '11 at 23:27
i enable a folder to be share through samba with all accounts in ubuntu. – laura May 15 '11 at 23:29
Hmm sorry then i don't really have an idea – K. Hendrik May 15 '11 at 23:39
seems like a PAM problem. could you try it and show us the last lines of /var/log/auth.log just after trying it? – santiagozky May 15 '11 at 23:42

This fix the problem.

sudo chmod +s /usr/lib/policykit-1/polkit-agent-helper-1

as simple as this...

share|improve this answer
One should ask why it was not +s already, as it is in a standard installation. – enzotib Sep 5 '11 at 12:19

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