Admin? I'm root! :-) No, I just play in single player mode, running the game on my own computer (and, of course, as a normal user, not from the root account).
I used to open the game from the menu, or via desktop shortcut, and like most people, I never bothered to look into the game's log files. One day, however, I just happened somehow to start the game from the command line. If you do this, you will see everything that is written to the log file live on the screen. I was installing or updating some mods at the time. If you select one in the game's mod manager, it will try to make the changelog button active. If there is no changelog, the button will stay inactive and no error will be logged; if there is a changelog with an error, an error message will appear on screen and in factorio-current.log. Once you're done installing/updating, the game will restart. I just happened to see a bunch of these messages because I had looked at a number of mods right before Factorio restarted. Had there only been one line, I would probably have missed it -- but several error messages spamming my screen? That was too much not to be noticed, so I got curious and looked into the changelogs to see what might be wrong. :-)