I have just installed a new instance of MS SQLEXPRESS 2014 on a dev server. During setup I set permissions to Windows Authentication and granted the Administrators group access to the SQL Server. However now that I have completed setup one of my developers is having difficulty creating a new db. I have checked permissions, settings, everything I can think of but I don't find any reason this capability is being blocked.
I thought a quick solution would be to update the properties for "BUILTIN\Users" and grant sysadmin Server Roles. However when I attempted this I received an error message stating "Cannot alter the server role 'sysadmin', because it does not exist or you do not have permission."
It seems obvious that the sysadmin Server Role exists so this leaves me at the conclusion that I do not have the proper permissions. Can someone guide me through this? What have I done wrong?