I encountered another interesting error during Exchange 2010 installation today. During the Organization Preparation I got the following error:

The requested object has a non-unique identifier and cannot be retrieved.Active directory response: 0000219D: SvcErr: DSID-031A0FC0, problem 5003 (WILL_NOT_PERFORM), data 0

The setup.log doesn’t give us much more detailed info:

I remembered from a Tweet by Helge Klein recently that the Active Directory schema has no mechanism for enforcing uniqueness of an attribute.

My first assumption was a duplicate sAMAccountName but I couldn’t find any evidence for that.

Then I checked for duplicate SID‘s, you can do this via NTDSUtil:

check duplicate sid

NTDSUtil creates a log file in the current directory (dupsid.log) and indeed I was having duplicate SID’s:

What made this very interesting is that the names listed here like Public Folder Management and Recipient Management are all created during Exchange 2010 installation.

This behaviour is described in Prepare Active Directory and Domains in a little note:

So what happened?

I did a P2V of 2 existing domain controller to test an AD upgrade in a Sandbox. After the AD upgrade I kept the sandbox and decided to test Exchange installation as well.

I first created a P2V of DC002, the least important domain controller, and put in online in the sandbox to test the P2V process.

Because the DC002 had the RID Master FSMO role it was possible to allocate a block (the same block) of relative ID’s in both the sandbox and the production environment.

A couple of days later I did the P2V of the other domain controller and placed it online as well. And this is where the duplicate block became a problem.

Because I am in a sandbox I could take the easy solution which is use the cleanup duplicate sid command in NTDSUtil:


Warning: the cleanup duplicate sid command will delete BOTH objects having the same sid!

Sidenote: It seems that the problem with the otherWellKnownObjects attribute I described earlier was actually caused by the Exchange Setup as well!

My recommendations  for P2V of Domain Controllers:

  • P2V all Domain Controllers at the same time.
  • If you cannot p2v all Domain Controllers at the same time, do not bring a copy online before you finished all P2V’s.
  • Make sure the RID Master is brought online LAST