So this isn’t especially data oriented, but for any developer who is constantly creating new VMs for development or testing this info might come as a pleasant surprise.
Over the years, when cloning VMs, sometimes by simply copying the VHD files and attaching them to a new machine, we’ve been told that we’ll cause problems because we aren’t creating machines with unique SIDs. As a result, we’ve had to use sysprep, sysinternals NewSID (discontinued) or the VM software of our choice’s cloning tool. Turns out however, our obsession with SIDs was all for nought. The following technet blog post by the author NewSID details why duplicate SIDs don’t matter:
Note that it is still official Microsoft policy to require cloned machines to be syspreped, and as such I would recommend following that policy in a production environment, but for us developers, copy away and stop worrying about your SIDs!