there are too many log files, still not able to understand what's preventing it to complete the login of the user; is it possibile that the beta 2 setup didn't complete, i wasn't there during the setup, so maybe it's someway at the reboot but the setup wasn't finished; another option is that there's somewhat during the login that stops the procedure, but i disabled LaunchAgents and LaunchDaemons with no luck... :-(

thank you Wawa_Apple i'll try, even f it seems related to the beta release... isn't it?