I have slow PC and I want to make Plasma5 more lightweight. Let's say I need only panel and Dolphin. For updates I will check manually in terminal.

Let's assume I don't need anything else. How to get rid of unwanted processes?
I don't need akonadi, automatic updates checking (I noticed process unattended-updates), discovery (I still prefer muon), reporting errors, remote logging options. Do I need SDDM for single user?
I know that many things can be unchecked in settings but I still use buggy Plasma 5.8 in Kubuntu 16.04. That's why I prefer to uninstall / permanently remove what possible.

I would begin with what is exposed through KDE settings. For example go to Settings > Startup and Shutdown > Background Services > Startup Services and uncheck there everything you don't want and need.

If file content indexing is not important to you, consider to disable it:

Code: Select all

kwriteconfig --file $HOME/.config/baloofilerc --group General --key only\ basic\ indexing true

Akonadi is a requirement of Akregator, KNotes, KOrganizer, KMail and apparently Calligra also, I think you can't get rid of it and keep these apps at the same time. It shouldn't be a problem to remove plasma-discover though... if I understand it right it is only a recommendation of the plasma-desktop package.

What you are doing now is removing stuff from a full installation, but you may find it easier to start with something more minimal instead (like KDE Neon distro) and only add those applications that you really want or need.