Rename Shared mailbox and reuse Primary Address

Chalee 12 Reputation points
2020-09-28T12:26:54.543+00:00

Hi All,
We are using Exchange 2016 and Outlook 2016. We have a
requirement to rename a number of large shared mailboxes and then re-use
the same email address to create a new shared mailbox which will forward the email to an
external domain.

My main worry is how to correctly rename the shared mail box
before creating and re using the primary email address in the new shared mailbox.

EG I have a shared mailbox called MailboxA with email address
MailboxA@keyman .com I need to create a
new shared mailbox with preferably the same name and it has to have the same email
address. So I want to rename MailboxA to "MailboxA-archive" and
change its default email address to MailboxA-archive@keyman .com

Then I will create a new shared mailbox called MailboxA and
add MailboxA@domian.com as its primary
address.

When I create the new shared mail box I have noticed it
doesn't get an X500 address but does get a LegacyExchangeDN.

Will I get any email routing issues as I am trying to
create the new shared mailbox with the same name as the original before it was
renamed? As the original had an x500 address will exchange route the primary
address to the archive mailbox rather than the new mailbox?
Any recommendation on the best way to rename the original
shared mailbox so I don't have issue when creating the new shared mailboxes.

Thanks
ChaLee

Exchange Server Management
Exchange Server Management
Exchange Server: A family of Microsoft client/server messaging and collaboration software.Management: The act or process of organizing, handling, directing or controlling something.
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  1. Lydia Zhou - MSFT 2,371 Reputation points Microsoft Employee
    2020-09-29T02:59:10.843+00:00

    @Chalee

    Before modifying the e-mail address of your shared mailbox, please check the email address policy it uses. By default, "Default Policy" is applied, and the address format is alias@Company portal .com. If so, you can modify the alias to MailboxA-archive, and MailboxA-archive@keyman .com will be added as the primary SMTP address according to the default policy. Then you can remove the previous email address MailboxA@keyman .com:
    28933-571.png

    When we create the mailbox MailboxA, an AD object is created as well. In general, we cannot just modify the displayname, alias and email address. I test in my environment, and found that I have to modify "CN=<mailboxname>" from ADSI Edit to change the distinguished name, so that I can create a new shared mailbox to use the old name. Otherwise, the following error occurs:
    28899-572.png

    Important: ADSI Edit must be handled with care. Modifying the attributes using ADSIEdit can cause significant issues with your infrastructure if something is done in a wrong way. We would suggest you make a backup before modifying.

    For the mailflow issue, the auto-complete cache in Outlook and OWA uses the value of the LegacyExchangeDN attribute of the previous MailboxA. Since the previous MailboxA still exists, yes, the messages should be routed to the old mailbox. You have to clear the auto-complete list manually. For your reference: Information about the Outlook AutoComplete list.

    If the mailbox size is reason for you to create the same mailbox, it's suggested to use archive mailbox and retention policy to reduce the size, or archive items to .pst manually.

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