Mark Russinovich’s article “The Machine SID Duplication Myth” posted November 03, 2009
I realize that the news that it’s okay to have duplicate machine SIDs comes as a surprise to many, especially since changing SIDs on imaged systems has been a fundamental principal of image deployment since Windows NT’s inception. This blog post debunks the myth with facts by first describing the machine SID, explaining how Windows uses SIDs, and then showing that – with one exception – Windows never exposes a machine SID outside its computer, proving that it’s okay to have systems with the same machine SID.
http://blogs.technet.com/markrussinovich/archive/2009/11/03/3291024.aspx
