I don't have much to add other than to say I am also experiencing this issue or one similar to it. I am running xfce on ubuntu 20.04 in a kvm virtual machine. The system was configured to boot to a command prompt with “systemctl set-default multi-user.target”, so when I want to run xfce this is done with "startxfce4".
(problem description) if you log in to xfce then immediately log out it will fail with one of these errors: session manager must be in idle state when requesting a shutdown gdbus.error:org.freedesktop.dbus.error.invalidargs: type of message, "(yb)", does not match expected type "(b)" - example scenarios: reach the desktop, wait 45 seconds or more, try to log out, it works normally reach the desktop, try to log out immediately, get an error, try a second time, sometimes it will work reach the desktop, try to log out immediately, get an error, sit there doing nothing for a few seconds, sometimes it will log out - I tried playing around with the file 50-guest-wrapper.conf as others had mentioned, but I did not notice any difference. I also have an identically-configured centos 8 vm and it does not have this issue. (uninformed guess) When reaching the desktop something related to lightdm or xfce is failing in the background, once a timeout is reached, things work as expected. -- You received this bug notification because you are a member of Ubuntu Touch seeded packages, which is subscribed to lightdm in Ubuntu. https://bugs.launchpad.net/bugs/1855350 Title: Will not logout or shutdown from guest-session Status in lightdm package in Ubuntu: Confirmed Status in xfce4-session package in Ubuntu: Confirmed Bug description: This is in Xubuntu 19.10, a regression from 18.04. xfce4-session 4.14.0-0ubuntu1. I enabled guest-session and logged in that. But there I can not log out or even shut down using the graphical way at least unless put Action Buttons on the panel and choose Switch User. If I run "xfce4-session-logout -l" I get error dialog saying: Received error while trying to log out GDBus.Error:org.freedesktop.DBus.Error.InvalidArgs:Type of message, "(yb)", does not match expected type"(b)" And in standard output there is: "Received error while trying to log out, error was GDBus.Error:org.xfce.SessionManager.Error.Failed: Session manager must be in idle state when requesting a shutdown" To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/lightdm/+bug/1855350/+subscriptions -- Mailing list: https://launchpad.net/~touch-packages Post to : email@example.com Unsubscribe : https://launchpad.net/~touch-packages More help : https://help.launchpad.net/ListHelp