Software can't be installed or removed because the authentication service is not available

Question

I'm trying to install flash via the software center and I get this error :

"Software can't be installed or removed because the authentication service is not 
available. (org.freedesktop.PolicyKit.Error.Failed: ('system-bus-name', {'name':  
':1.51'}): org.debian.apt.install-or-remove-packages" 

I checked the startup applications and found that the policy kit authentication agent was checked.

I then tried to use /usr/lib/policykit-1-gnome/polkit-gnome-authentication-agent-1

and received this error message:

(polkit-gnome-authentication-agent-1:25835): polkit-gnome-1-WARNING **:  
Unable to determine the session we are in: No session for pid 25835

The error appears to be avoided by running software center in root mode by using

gksu software-center  

or by installing it via command mode e.g. sudo apt-get install flashplugin-installer

Solution

Since PolicyKit seems to be installed and apt-get is working, try the following command

sudo apt-get --purge --reinstall install software-center software-properties-common software-properties-gtk

Comments

[Rohith Madhavan]

Does apt-get work for you?

[James Wynne]

I was able to preform sudo apt-get update

[Wilf]

N.B. you can install flash and other things with apt-get instead of using the Software center: askubuntu.com/a/33134/178596

[Rohith Madhavan]

For the time being, you can install flash using sudo apt-get install flashplugin-installer

[nnyby]

gksu software-center hangs for me