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Broken ForestPrep

Friend of mine tried to promote Windows Server 2012 into Windows Server 2003 SBS environment. He had installed Windows Server 2012 Server. He also installed role Active Directory Domain Services. When he tried to promote new installed Windows Server 2012 into existing SBS domain he received following error:

Error was generated while Windows Server 2012 tried to do preparation of AD forest. So I have tried to do it using command line:

So same error (Adprep could not retrieve data from the server through Windows Managment Instrumentation WMI). Some problem with WMI on existing domain controller. I have tried to rebuild WMI from scratch using this article. No luck. Message saying “Access is denied” was not true, because account used to run setup.exe /forestprep was Enterprise, Domain and Schema Admin. When I read this article I found out that DCOM has to be enabled and accessible when doing domain controller promotion. So I looked into configuration of old domain controller following way:

Run command dcomcnfg.exe

Browse down to Component Services -> Computers -> My Computer. Right click and select Properties. I found that DCOM was disabled:

So I enabled it with following settings:

…and I was able to promote Windows Server 2012 as a new domain controller. No more access or WMI errors.

This was really hard one to find out 🙂

  1. Michal_F
    March 20th, 2014 at 13:48 | #1

    Good Job 🙂

    The interesting think would be if you would migrate to WS2012 Essentials a then uninstall Essential role from new WS2012. This transition is official supported. I am not SBS expert, but i think this is somethink that sbs 2008 migration preparation tool is setting.

    Another question, is the DCOM disabled on all MS SBS systems ? But maybe it have meaning, SBS is designed to be single DC.

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