Windows Username maximum length
Question
What is the maximum length of a Windows domain + username? That is, what is the legal limit for a domain/username in Windows?
Solution
Read this
for windows 2000: http://technet.microsoft.com/it-it/library/bb726984(en-us).aspx
for windows 2003: http://technet.microsoft.com/en-us/library/cc783323.aspx
OTHER TIPS
The maximum lengths are hash defined in lmcons.h. DNLEN is the maximum domain length and UNLEN is the maximum user name length.
In the version of this file I have on my XP machine (installed as part of Visual Studio 8), DNLEN = 15 and UNLEN = 256.
There is a constant UNLEN which is defined in Lmcons.h that defines the maximum length of a username
compmgmt.msc allows usernames for local account at max with 20 characters. dsa.msc allows domain user names to be 256.