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.