Hello I can't seem to find solution for my CreateProcessAsUser problem. I keep getting The parameter is incorrect error. but I dont even know which parameter is incorrect. Could anyone please look into my code and help me to find out what causes this error. Link to function: http://msdn.microsoft.com/en-us/library/windows/desktop/ms682429%28v=vs.85%29.aspx ;~ CreateProcessAsUser(hToken,NULL,app_path,NULL,NULL,FALSE,CREATE_UNICODE_ENVIRONMENT |DETACHED_PROCESS,lpEnvironment,NULL,&StartUPI