This means that Blender can't load the addon.Waterbottle wrote: ↑Thu May 17, 2018 12:08 pm Oh and also I always get an error when I save blender and the open it again later .in the nodes there is an error message saying"undefined socket type" and it automatically switched to blender render and in the rendering engine's list I cant find luxrender. sorry, I am a newbie.
Make sure that you are using the official Blender 2.79b from blender.org, not some version from another website, or a custom build, or from some PPA.
If you are using the official 2.79b and it still does not load, you can open the console with Window -> Toggle System Console (in Blender, menu on the top) and copy/paste the error message here.