In this post I am going to explain how to enable GUI root access on Debian 9 – KDE5 Plasma (thanks to Dario Alejandro for the instructions). The following instructions vary those published in previous posts, as those explain how to enable Gui Root Login in Debian 8 and Debian 9 for gnome.
At this point I should once again warn you that using root access can ruin your whole system. Don’t use it if you don’t know what you are doing!
One can get GUI root login on KDE5 Plasma running sddm as follows:
1) set the root password “sudo passwd root”
2) in /etc/sddm.conf change MinimumUid=1000 to MinimumUid=0
3) in /etc/pam.d/sddm comment out “auth required pam_success_if.so user != root quiet_success”
4) Reboot into the glory of root access! Don’t bjork your machine now!
I hope this helps!
Economic Theory Blog 
Where is the /etc/sddm.conf file? I just installed Debian 9.1 on my system.
Hi! The file is called sddm.conf and should be stored in the etc directory. Are you sure that you installed KDE5 Plasma? In case you installed Gnome, check out this post: https://economictheoryblog.com/2017/05/02/how-to-enable-gui-root-login-in-debian-9/
Cheers
I do have KDE installed. Its the standard KDE the install routine installs for Debian version 9.1. I did find a /etc/sddm directory with only an Xsession file contained within. I suppose I could create smmd.conf file in the /etc directory with the information above.
I have been using Debian since version 3.1 (Sarge). Each version gave little resistance to logining in as root.
Unfortunately, I do not have KDE installed at any of my machines, so it is hard for me to verify why it isn’t working. I will install KDE once I have a bit of spare time and check if anything changed. Please drop a note if in the meantime you find a workaround.
A little late to the party, but I thought I’d throw in my nickel’s worth (inflation, ya know!) for anyone else that ends up here like I did today.
The file is indeed /etc/sddm.conf, but seems it isn’t created during installation. Following Dario Alejandro’s instructions (which, BTW, work with Debian 9.4.0 and probably earlier versions of Debian 9 as well) causes the file to be created and is thus the easiest way to do step 2. Then, just continue with steps 3 and 4.
On my recent kubuntu 16.04.3 install I found the sddm.conf in /etc/init/ instead of /etc/. There may be slight differences between Debian and kubuntu file locations. Try using “locate sddm.conf”.
Thanks you for your remark. There might indeed exist slight difference between various distributions.
For the record, that file exists on Debian as well, but it isn’t the file needed to enable root GUI login.
there is no sddm.conf file in the etc directory.
there might exist slight differences depending on the distribution that you are using. Dario Alejandro dropped some very useful comments in this direction.
Edit to previous comment: running kubuntu, you can change the minimum uuid by going to Settings —> System Settings –> Startup and Shutdown –> Login Screen (SDDM) –> Advanced –> Change Minimum UID to 0. You still have to comment out “auth required pam_success_if.so user != root quiet_success” in /etc/pam.d/sddm
Cool! Thanks for the hint. Unfortunately, I do not run kubuntu, but I’ll make sure that other user find your instruction. Cheers!
I’m a little late to the party, but I just wanted to say for anyone else that shows up here as I did today, that these instructions also work on Debian 9.4.0 and so this is the easiest way to do step 2. Then, as Dario points out, you have to continue with steps 3 and 4.
Thank You !
No Problem! cheers ad
thanks dude! it worked on my KDE Neon Linux
Glad it helped!