http://wmug.co.uk/wmug/b/scambler/archive/2010/06/03/the-machine-sid-duplication-myth.aspxExtract from Mark Russinovich’s blog On November 3 2009, Sysinternals retired NewSID , a utility that changes a computers machine Security Identifier (machine SID). I wrote NewSID in 1997 (its original name was NTSID) because the only tool available aten-US6.x Production