$ rpm -qa '*polkit*' libpolkit-qt-core-1-0.112.0-alt1 polkit-0.113-alt2 libpolkit-gir-0.113-alt2 polkit-gnome-0.105-alt1 libpolkit-0.113-alt2 xfce-polkit-0.2-alt1 $ I have installed polkit-gnome by accident in ALT Education 8 system (with Xfce), and now an error is reported every time I login into Xfce from the dm: XFCE PolicyKit Agent GDBus.Error:org.freedesktop.PolicyKit1.Error.Failed: An authentication agent already exists for the given subject I suspect they should conflict with each other. I've found a sismilar discussion here: https://ask.fedoraproject.org/en/question/24803/gdbuserrororgfreedesktoppolicykit1errorfailed-an-authentication-agent-already-exists-for-the-given-subject/ After removing the package polkit-gnome, this error disappears. After installing it, this error appears again.
P8 not supported nowaday. Fixed in Sisyphus (ALT bug #42060).