I am new in SP Foundation, I have to create a new Site Collection from the Central Administration. I have to set the Primary Site Collection Administrator with a local user, I have no domain and my SP 2013 Foundation is a stand alone installation.
I tried with machine_name\user_name
but it is not working.
remove the machine name and only use the user name! if in dout look in active directory users and computers to see the local user account that your using to make sure its correct..... Make sure that the machine name is correct –