Out of Office Hours

Going way back into the time machine, there were third-party utilities like GhostWalker (remember Ghost?) and NewSID (from Sysinternals) that could “prepare Windows for imaging.” Eventually, Microsoft said “you must use Sysprep, as that’s the only supported way to prepare an OS for duplication.” That should be the end of the story right? Not quite.

But then there were blog posts like “The Machine SID Duplication Myth” from Mark Russinvich that said “SIDs don’t matter.” And people again said “we don’t need to sysprep,” ignoring the fact that sysprep does a bunch of stuff (mostly undocumented) to prepare an OS for duplication. More KB articles and documentation were released to reaffirm that “Sysprep is required for OS duplication.” End of story? No.

Now in 2026, we get this article:

https://techcommunity.microsoft.com/blog/windows-itpro-blog/hardening-administrative-actions-what-it-pros-need-to-know/4503956

At a high level, this says “duplicate SIDs are bad” and that “you need to get rid of the duplicates” because they cause security issues. A workaround is available until the end of 2027, but it is something you need to fix.

I certainly hope this will finally be the end of the story.