SID duplicated mystery on a host but not created from an image file ?!?

As you maybe know, when more than one server are using the same SID it can keep from sending emails from OWA (Exchange 2010)

This is exactly what we've been living with recently.  Both DCs (VM) we using the same SID.  But each Exchange server had a unique SID.  

So I demoted a DC.  Then a new VM has been created.  This time Windows 2008 R2 has been installed from the CD, no image, no sysprep, nothing.  I ran DCPROMO.  

But the new server has the same SID !    How come ?  It has a different name, it comes from a fresh Windows installation.  I don<t get it but maybe someone knows ?

However, Exchange is no longer preventing the emails to to be sent out.  

Thank you
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Dupilicate SID's occur when cloning workstations and servers.  You should use a SID Changer whenever initializing a new workstation/server from a clone.  NewSID.exe (can search and dowload free from internet) is an application can be used to change the SID on such clones.  In the future you should consider using Sysprep which automatically generates a new SID.
quadrumaneAuthor Commented:

But as I said, the new server has not been created from an image or from a cloned vm.  So it shouldn't have the same SID.
Actually, that information is outdated and no longer correct. NewSID has been retired as it is not necessary. Duplicate machine SIDs should not cause problems. The NewSID program, as well as many other SID changers, have many various issues on Windows Vista, Windows 7, and Server 2008. Read the article here:

The issue is caused by cloning a PC already on the domain. This creates duplicate domain SIDs, which will have many various problems. It is highly recommended to remove the PC from the domain and then use sysprep prior to imaging a system.

As for the duplicate SIDs you are seeing on the DCs, are you referring to the domain SID or the machine SID? The local SID on the DCs should be the same, while the domain SID should be the same as the local SID except for the very end of it which should be unique on the domain (similar to having how RIDs). See here:

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quadrumaneAuthor Commented:
All servers with the same SID but one have been completely removed.  But I had to keep one (a DC)  Maybe this server is assigning the same SID to all new DCs although the new DC  has not been created from an image.  
To restate my above comment:
As part of promoting a PC to a DC, it will change the local SID to match all the other DC's local SID. It should also create a domain SID that is the same as the local SID except with another part appended to it, which should be unique. Having duplicate machine SIDs for all the DCs is normal. Just make sure the domain SIDs are unique.
quadrumaneAuthor Commented:
Here is what I got:

The new server (Windows 2008 R2 has been installed, not from an image)
SID for \\S1-DC-002:

the old server (this one has been created from a clone)
SID for \\S2008DC01:

It looks like it is the local SID
Using psgetsid.exe I'm assuming. I just did the same on my DCs and got the same type of results. All DCs were created from scratch. This is normal.

You can check the domain SID in the attributes of the computer via LDAP tools or Active Direttory Users and Groups.
quadrumaneAuthor Commented:
but in the attribute in object editor the same is almost the same except for the last 4 digits


That's good & completely normal. That is what you should be what you are seeing.
Wow - I need to slow down my typing! I meant to say:

That's good & completely normal. That is what you should be seeing.
quadrumaneAuthor Commented:
Ok I now understand.  I didn't check the local SID before promoting the new server.  So now it has the same local SID but it's normal.

Correct me if I'm wrong
That is correct.
quadrumaneAuthor Commented:
And me I should refresh my browser ;-)  Ok so all is said, all is normal, all is good

Thank you very much !
geowrian:  Thanks for the info... shows how long it's been since I've ran into this problem.  It has long been common practice not to clone Windows installed drives; as mentioned, a number of years since I've seen the problem.
No problem. I have been following Mark's website and blog for years, so I am aware of why he made the tool. I was also surprised by his findings as changing the SID was common practice. I also assumed it was necessary like nearly everybody else.

Another department at my employment also encountered a number of the SID change issues on Windows 7 computers that were being imaged, so some good reading and good communication saved everybody a lot of headaches.
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