Q:

The name > org.freedesktop.PolicyKit1 was not provided by any .service files

When attempting to launch system-config-users from command line, I get the following warning, and the tool does not open.   I'm using CentOS 7 with Mate 1.8.1.

WARNING **: Error enumerating actions:
  GDBus.Error:org.freedesktop.DBus.Error.ServiceUnknown: The name
  org.freedesktop.PolicyKit1 was not provided by any .service files
Error checking for authorization org.freedesktop.policykit.exec:
  GDBus.Error:org.freedesktop.DBus.Error.ServiceUnknown: The name
  org.freedesktop.PolicyKit1 was not provided by any .service files

yum list polkit*
Installed Packages
polkit.x86_64   0.112-5.el7 @anaconda
polkit-devel.x86_64 0.112-5.el7 @base    
polkit-docs.noarch 0.112-5.el7 @base    
polkit-gnome.x86_64 0.105-6.el7 @epel    
polkit-pkla-compat.x86_64 0.1-4.el7  @anaconda

What is missing from my system to cause this error? 

A:

I just had the same return when installing deluged on arch, I typed:
 systemctl start deluged

I tried with sudo and it worked fine. Seems to be a group permissions issue. 
All I did was enable permissions for my user account and then typed:
 sudo systemctl start deluged

worked like a charm.

A:

To clarify and summarize SNP22's post: You probably just forgot sudo.:
sudo systemctl [...]

Absolutely misleading warning ...

