8 thoughts on “Decommission an Exchange Resource Forest in a hybrid environment”

  1. great article, would you mind to share your import script template?
    I have a similar scenario where I’m not sure if have to migrate only those :PrimarySmtpAddress, RemoteRoutingAddress, ExchangeGuid, Alias, EmailAddresses (beware, this is a multi-value attribute), HiddenFromAddressListsEnabled EXCEPT by DisplayName (which we can’t move – otherwise we’ll break an accounts forest/domain standard for DisplayName which is currently different between the 2 domain).
    we moved user out of synced ou on resource forest the user is not shown on accounts forest any longer even existing on its ADDS and being on synced OU, something went wrong with our alpha test.


    1. Hi Thiago,
      I don’t have this script anymore. I have been fiddling with PowerShell commands until it worked and wrote it down.
      Your second question (regarding the synced OU) is not clear to me, if you want you can send me an email or leave message on the ‘About’ page.


      1. hey I got that solved, domain1: accounts, domain2: resource
        removing domain2 or synced ou from sync (azure ad connect on domain1) where users identities are merged and moving EXC attributes from domain2(resources) to accounts(domain1) running delta sync solves doesn’t break the process and allow us to decommissioning exchange from domain2 . great thanks. (I had to use 3rd party tool to sync exchange attributes once powershell was giving me a hart attack on exporting multi valued and binary/hex attributes (however, I’ll work on having a function to do that to me)


  2. Hello Jaap,

    I will have to do something similar in my environment but without Office 365, and migration will be performed between Exchange 2016 and 2019.

    Is it safe to assume that steps one and two still apply? Any other post setup recommendations I should follow?



  3. i have been working on a project exactly like this and now i m in the last step decommissioning but i need SMTP so i installed exchnage on account forest
    now i have questions regarding to the script of moving attrtibutes
    why shall i need displayname, and exchangeGuid
    second in azure ad connect shall i in the resource forest
    1- remove the synced OU or
    2- stop the connector
    3- delete the connector of resource forest


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