I have updated my kubuntu 14.10 to kubuntu 15.04. And now after boot, when I enter my password on welcome screen, I will get black screen. It's looks like screen powered off. No cursor, no change brightness. Nothing. And when I try switch to text consoles (Ctrl+Alt+F1) nothing happening. If I doesn't login in welcome screen I can switch to text console.
I may have a solution, I've been trying to figure out what happened for a few days now. Deleting all ~/.cache and ~/.config is not a great idea, as those could be needed but. . .
In ~/.cache, I have deleted only the files with a 14.04 boot DVD, but I have kept the folders:
activityswitcher_wallpaper_preview.kcache event-sound-cache.tdb.093cbe7e51f0423cb8a1384115f450a1.x86_64-pc-linux-gnu icon-cache.kcache ksycoca5 ksycoca5stamp motd.legal-displayed (0 kb) plasma-svgelements-air_v1.0 plasma-svgelements-breeze-dark_v0.9.7 plasma_theme_breeze-dark_v0.9.7.kcache [...] plasma_wallpaper_preview.kcache
After rebooting, the desktop was fine.
This has troubled me for some time now. I noticed it happens when I put Kubuntu to sleep or shut it down with a dual monitor set-up and then trying to start it with the laptop screen only. Anyway, here's what I found - one particular folder is responsible for this mess. Deleting it fixes my problem.
Here's what to do. Once you get the black screen go to a tty (Ctrl+Alt+F1) and do the following:
rm ~/.local/share/kscreen sudo killall sddm
Then enter your password and login. Everything should be ok. Hope this helps ;)
I too had the same problem in the fresh install of kubuntu 15.04 64 bit.
- Press Ctrl+Alt+F1 after the system has started
- System will prompt to login give your login name and press enter
Enter the password
mv ~/.kde ~/.kde.old mv ~/.cache ~/.cache.old shutdown -r now
If you can get your gui on next boot don't forget to change 'start with empty session' in 'desktop session' in 'System Settings'
TL;DR: Check if you have sufficient space in
/home. Insufficient space prevents xOrg server to start.
To get the system back, you can run
startx in the terminal, which should give you some hints, as indicated by this reddit thread. This command starts the xOrg server. The proposed solution in the reddit thread with changing
~/.xinitrc didn't work for me.
startx did indeed get your system back, you could reboot, back into the terminal and look if the xserver isn't running by running
xset q as indicated here. Since
echo $DISPLAY didn't return anything for me, I found these solutions, as
startkde didn't work either (
startkde would start the kde session). Most importantly,
/home should have enough space (check disk usage with
These solutions finally proved to be worthy, as I simply had no space left. After cleaning up some files and rebooting, KDE did start as usual.