Can't logon to xfce4

I'm using Ubuntu 18.04 bionic and installed the xfce4 package. However, when I choose "Xfce session" in the login manager, it does not log me on to Xfce4 but instead throws me right back to the login window. Why is this and how can I fix it?

Solution 1:

I get this same issue if I go from another Desktop Environment to Xfce4 (Xubuntu). As long as I have chosen the Xfce4 (Xubuntu) and tried to log in and it loops, I then reboot the system and then it should still be on the Xfce4 (Xubuntu) then I can log in. It doesn't happen on every DE switching back to Xfce4.

Update 07/02/2021:

You can fix this permanently by adding the following line to /etc/gdm3/PostSession/Default (this also works in 20.04 using GDM3):

killall -9 -u $USER

So that the PostSession/Default file looks like:

#!/bin/sh
killall -9 -u $USER
exit 0

Then just logout and log back in using the DE of your choice.

Hope this helps!