Ubuntu – Black screen after login Kubuntu 15.04

15.04kubuntu

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.

Best Answer

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.

Related Question