The rules for logon names are:
– Local logon names must be unique on a workstation.
– Global logon names must be unique throughout a domain.
– The practical limit for a logon name is 64 characters, but the technical limit is 104 characters.
– A Pre-Windows 2000 logon name, up to the first 20 characters of the logon name, is assigned to all accounts (sAMAccountName).
– The Pre-Windows 2000 logon name must be unique throughout a domain.
– Logon names cannot contain / \ [ ] : ; | ” = , + * ? < >. While spaces are legal, DO NOT use them!
– Logon names are case aware BUT NOT case sensitive.