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

  • Does apt-get work for you? – Rohith Madhavan Nov 15 '14 at 9:41
  • I was able to preform sudo apt-get update – James Wynne Nov 15 '14 at 9:48
  • N.B. you can install flash and other things with apt-get instead of using the Software center: askubuntu.com/a/33134/178596 – Wilf Nov 15 '14 at 12:10

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
  • 1
    The command worked fine still receiving same error although i can get the software center to run fine by using "gksu software-center" – James Wynne Nov 15 '14 at 9:58
  • For the time being, you can install flash using sudo apt-get install flashplugin-installer – Rohith Madhavan Nov 15 '14 at 9:59
  • gksu software-center hangs for me – nnyby May 4 '15 at 14:49

I came across this solution on http://looselytyped.blogspot.com/2013/04/making-ubuntu-software-center-work-with.html

Give the following a try:

sudo apt-get install polkit-kde-1

You might need to logout or restart for the changes to take effect.

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