This was a shocker to me as well when I read this a few months. I would say to proceed with caution; although it is true that Windows may not use the machine SID discriminately but other applications might. Many many years ago we ran into a problem where GhostWalker had to be use to generate new SID to fix a boot issue. Firm. From: Al Puzzuoli [mailto:[log in to unmask]] Sent: Wednesday, August 04, 2010 3:00 PM To: [log in to unmask] Subject: [MSUNAG] Apparently, SID Duplication Doesn't Matter? Just came across the following article, If anyone out there should know this stuff, it's Russinovich, but this is making me rethink what I thought I knew. http://is.gd/e2Inb --Al