Probably solution number 4 from here https://forum.faforever.com/topic/4256/solutions-for-common-errors-with-the-faf-client-launcher-or-supreme-commander @magge said in Solutions for common errors with the FAF client launcher or supreme commander: Reason Program is blocked or has wrong user rights Make sure security software is not blocking the client Make sure your windows account has rights to run the software Remove "C:\ProgramData\FAForever" folder; and reinstall FAF For testing purpose, run the client with admin rights.