Hello I'm running the software on windows.
In the rendering projects dialog there is an option to shutdown the computer after rendering.
However I am not able to select that option, it is greyed out.
Can anyone tell me how I can select this option?
Thanks!

The shutdown feature is using a KDM dbus command (KDM is KDE's login manager). You can find some useful info in this thread:
viewtopic.php?f=272&t=116004
Also, some solutions can be found on https://answershark.com/programming/. There are you can find some tips and tricks. And I advice you to read this therad:
viewtopic.php?f=66&t=30392&start=10