Thank you very much! Really! Every time this forum surprise me!
As usual I forgot to check with more attention the Kixtart Guide, and I have seen the function SIDtoName too late!

Now I'm trying to create a script to have a list of users not recognized from the server, so I will be able to check it and verify correctly!

My idea was to create 1 file .txt for every machine with the list of SID. After with ReadLine check every line and try to give a name for every SID, or an error message.

Is it correct? Someone has an idea to realize a script more fast?
Thanks for your help!