If wayland does not start properly andx11 works as expected, check your ~/.bash_profile file. If it contains contains command exec startx, remove that line (and the surrounding if...fi statement). See this forum thread.
Thank you, i know, but clicking on the “news” button in the welcome app brought me to this place. And as many new users will be using the welcome app, i wanted to prevent that they would be confronted with a dead link.