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Installing Exchange 2010 "Coexistance Error"

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  • Installing Exchange 2010 "Coexistance Error"

    Got a bit of a strange one here, I hoping someone might be able to give a bit of advice?

    I'm trying to migrate to Exchange 2010 from 2007 - but I'm getting the "coexistence between exchange server 2010 and exchange server versions older than exchange server 2007 sp2 in the same active directory site is not supported" error when trying to install Exchange 2010

    I am currently running Exchange 2007, but I know that we migrated from Exchange 2003 to 2007 (before my time at the company) I have a feeling that the 2003 server was not decommissioned correctly, which is what is stopping me installing Exchange 2010.

    At first I had a look in both ADSI and PowerShell, and the original 2003 Exchange server kept showing up. No roles are assigned to the 2003 server, and everything has been working fine on the 2007 Server. Obviously, the original 2003 server is now on the scrap heap, so it's not possible to fire it up and decommission properly...

    After a bit of reading I went ahead and deleted the old 2003 server using ADSIedit as per Microsoft recommendations. This seemed to do the trick and using the get-exchangeserver command in PowerShell, only the current 2007 sever was returned.

    However, when trying to install 2010 I still get the "co-existence" error.

    I've ran all the /ps /pl /preparead /preparedomain commands, and all passed with flying colours.

    The only other thing I've noticed is that we still have two Administrative Groups - the second is from the original Exchange Environment - is it possible to delete this whole admin group?

    I'm bang out of ideas? Any advice would be very much appreciated.....

    Thanks in advance

  • #2
    Re: Installing Exchange 2010 "Coexistance Error"

    Which version of Exchange 2007 are you running? As the error message states E2010 can coesist only with E2007 SP2 or later.


    • #3
      Re: Installing Exchange 2010 "Coexistence Error"

      Exchange 2003 being present wouldn't cause this problem, as Exchange 2010 and 2003 can co-exist.
      The admin group shouldn't be removed really, as that can cause problems.

      If I had been presented with the error I would have only looked at one thing - your Exchange 2007 server. If it is not already on SP2, then take it to SP2 or SP3, then attempt the installation again.

      Simon Butler
      Exchange MVP

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