I have a user which has only Adding permissions which means that the user can only add items to a list. But I want to implement some logic in Title column with an even receiver.

But the problem is that I cannot update the item due to the permissions issue.

I have tried to use SPSecurity.RunWithElevatedPrivileges as follows but it is not working. I have the following event and code:

public override void ItemAdded(SPItemEventProperties properties)
                DateTime data = DateTime.Now;
                string dt = data.ToString("yy");

                properties.ListItem["Title"] = "KPM-000" + properties.ListItemId + "/" + dt;  
                EventFiringEnabled = false;
                EventFiringEnabled = true;

But this event wont work, it throws an exception AuthenticationException