MX Linux Forum

While booting or rebooting sometimes the login screen does not appear in KDE, i.e. the dreaded blank/black login screen. If that were to happen to you please try to see if the following troubleshooting steps work for you. Please do note that these are applicable for KDE. Do not know if these will work for XFCe or other Desktop environments.

First Step is burn SystemRescueCD or MX LiveUSB onto a flash/usb drive and boot from it. After booting System Rescue CD, run the following commands for all the ext2/3/4 partitions that you have It is assumed that /dev/sda1 is the / (i.e. root) partition for your MX Linux installation. It is also assumed that ext2/3/4 is the partition type that you have used for root. If not then remove the option -t ext2,ext3,ext4 and execute the command. Repeat it for all the MX Linux partitions that you have. Including /home and others. Ignore /swap partition. If you are using a NVMe drive then /dev/sda1 will have to be replaced by /dev/nvme0n1p1, /dev/sda2 will have to be replaced by /dev/nvme0n1p2 and so on. To find out what are the drives and partitions that you have for MX Linux give the following command from a terminal of SystemRescueCD or MX LiveUSB. This command will list all of the partitions/disks that have been detected. IF this works, great. Do not throw away the SystemRescueCD or MX LiveUSB that you have just burnt onto the flash drive. It will be useful to you in the future. If this step does not work then proceed to step 2.

Second step, check where you get the blank screen. Typically the first screen that you see is the GRUB screen of MX Linux, which will have 3-5 options displayed. The number of options will depend on whether you are dual booting your machine. Whether you have multiple Linux Kernel installed and so on. If GRUB menu is itself not displayed then to fix it we will use the MX LiveUSB. Boot using the MX LiveUSB and use MX Boot Repair application. The first option, i.e. "Reinstall GRUB Bootloader on ESP, MBR or PBR(root)" should be your go to default choice. If this does not fix your issue with GRUB then please raise an issue in the MX Linux forum. IF this works, great. If GRUB is not your issue or GRUB is now available but still you are getting a blank screen after selecting the OS then proceed to Step three.

Third Step. This will apply only if the first step does not fix your issue and you are able to select the MX Linux OS in GRUB menu. Typically after the OS is selected in GRUB the KDE Login screen should be displayed. This step will help you if you do not get the login screen. Try to see if you can use the key combination CTRL+ALT+BACKSPACE. This should ideally kill X or wayland and take you to a prompt. If that happens then at the prompt enter the command "startx" and see if you are able to log into KDE Desktop. If you are able to login into the desktop then have a look at the logs inside /var/log directory. Namely dmesg, syslog, X.org.0.log and other log files. That will have some indication on what has gone wrong. Backup your data and profile information. And then reboot to see if you are still getting the blank screen. IF this works, great. If not then proceed forward to Step four. If this workaround works, but you have to do it after every boot/reboot then raise an issue in MX Forum with the required log file details.

Step 4. This is a bit delicate step. For those who are not comfortable in editing or working in terminal/console please do not proceed forward. If you are on the fourth step then it is assumed that you are able to select the OS in GRUB but are still getting a blank/black screen in place of the KDE Login screen. Reboot your computer and enter the Grub menu of MX Linux. Before the timeout of 5 seconds happens, select the OS option that you want to boot into and press "e" on the keyboard. Look for options like quite splash or quite or splash. Delete the quite option and change the splash to nosplash. The removal of quite option will lead to more verbose logging into dmesg log files and other files. Make sure that you do not delete anything prior to or after quite splash or quite or splash. After making the changes press the key F10 on the keyboard and see if the login screen appears.

IF Step 4 does not work then raise an thread in the MX Linux Forum. Outline the steps you have done and include log files.

Hi,

you described trouble sources outside of kde - but kde has itself known problems with certain hardware:

• One reason for a black screen with blinking cursor is a crashing sddm-display manager.
  In this case you don't get any error message - just a system that looks like dead (and time to boot is 4-5 times longer than normal).
  Here you can switch to another console with ALT+F2 and login as root.
  Install lightdm with "apt install lightdm" - this should rise a configuration menu where you can select lightdm as default display manager.
  If you want to change display manager at later time call "dpkg-reconfigure lightdm" or after change to sddm call "dpkg-reconfigure sddm".
• Another reason is a crashing plasma session. In this case you'll get a black screen after login, right after MX-animation - and after some time an error message pops up telling you about the crash. Sadly there's no way to change the crashing session.
  In my case I had to disable Xinerama-option from xserver. Don't know if there are other solutions.

What Is most surprising is that SDDM does not seem to write to any logs anywhere. If it crashes or has issues.

Yes you are right the MX -animation does cause issue. I have faced this issue multiple times. But I have been unable to get to the root cause of it.

I have not tried lightdm instead of SDDM. Will try it out. Thanks.