No networking in recovery mode

I am running UbuntuGnome 17.04 which runs as it should, but when I trying to enable networking in recovery mode, the system tells me /etc/default/rcS is missing. As well as there is some unknown group "power" in message bus configuration file when trying to connect. It won’t connect.

I found an old config file for rcS which tells me that it belongs to “initscripts”. I could not install initscripts, as it is outdated. But creating the file in the original way by using copy and paste, the first error didn’t appear again but the unknown group "power" in message bus configuration file is still present.

Is there some way to solve this? Maybe by introducing the group “power” somehow, or due to install or purge some packages? I read something about a thermald bug, so I reinstalled and reconfigured it, but without having any luck.

Thanks a lot.