Was loading patch 18.104.22.168525 and got a virus alarm from Avira. Now I get a “You do not have the necessary authority for this action” message. The game is unplayable.
Did you use a torrent? I hope not.
Uninstall SC, then use your anti virus to scan your computer again and get rid of anything that shows. Then reinstall SC without using torrents.
Try to reinstall game and game launcher