Hi.

I have same problem, at least most of the symphtoms are the same. I found a workaround - you have to pick Plasma session type from dropbox on the left side even it is already selected. After picking the Plasma sesion I'm able to login to KDE.

Hope this helps to use KDE until the problem is solved permanently.

Regards
ArtūrasB.

Hi, I met the same issue.
In arch, if you use "useradd username" to add a user, there will create a user without home directories. So when you try to login, it will comeback to the login screen.
Try to use "useradd -m username" to create your user. https://wiki.archlinux.org/index.php/users_and_groups