Plasma 5, missing functions: e.j. Removable Devices in in-System Settings. (I
used this to automatically mount some Blu-Ray Disk.)

The solution.


1-  Changing the /usr/share/kde4/services/kded/device_automounter.desktop line
from...

> X-KDE-Kded-phase=1

to:
> X-KDE-Kded-phase=0

2- Starting 'Removable Device Automounter' from the Service Manager using

kcmshell4 kcmkded

3- Choose the right options from the KDE 'Removable Devices module using

kcmshell4 device_automounter_kcm


Daemon must be running

The 'Removable Device Automounter' Service, another KDE(4) control module,
needs to be running. Check with:

$ kcmshell4 --list | grep kcmkded
kcmkded                    - KDE Services Configuration


The Removable Device Automounter service will be running after a reboot.


Source:
http://askubuntu.com/questions/613313/kde-plasma-5-missing-removable-devices-option