Today, we had lost of power supply. I unplug my laptop from power cable. After power is restored, I connect it with normal configuration. Problem was mouse was not responding, so I reattach it to different active hub. Mouse start work, I relogin... Problem was... I lost settings... again. All settings was the same, but wallpaper and plasmoid was lost. Also, when I go into management mode and select manage monitors, I had only two screens... Previously I had many screens there.

That's all nothing new. Real problem was: I do not known how restore plasma settings from backup. I try to copy ~/.config/plasmarc ~/.config/plasmashell . But this did not restore my settings. Any suggestions?

I discovered that deleting some directories from cache ~/.cache/* (?) and logout will cause plasma lost one's settings. I thought it is safe to remove cache directory.

For someone, who's need to backup plasma settings, it's under ~/.config/plasma-org.kde.plasma.desktop-appletsrc . I hope nobody will lost data.