Distribution List

Hi @Glenn Maxwell

Thank you for posting your question in Microsoft Q&A. 

We understand that you are considering to add users to a DL using CSV file. We glad to assist you this part.  

Here is my response to your following question. 

1.Should UPNs or email addresses be used in the CSV file when adding members to a distribution list in Exchange Server 2019? 

As my research,  it is recommended to use email addresses in the CSV file for the -Member parameter when adding members to a distribution list in Exchange Server 2019. I have not found any official documentation that explicitly states a preference for using UPNs over email addresses. However, in environments where UPNs differ from primary email addresses, using email addresses may be more straightforward for managing mail-enabled objects. While UPNs are valid (as they uniquely identify users in Active Directory or Azure AD), they are more commonly used for authentication (for example login to Azure AD-integrated services) rather than mail-related operations. Using email addresses helps avoid potential confusion, especially when dealing with mail-enabled objects like distribution lists. 

You can refer more via: 

Add-DistributionGroupMember (ExchangePowerShell) | Microsoft Learn 

Official recommendation to UPN equal to SMTP/email address | Microsoft Community Hub 

2.Membership Approval For on-premises DLs and Exchange Online DLs, will the above syntax work if the DL has any of the following membership settings? If not, how can I modify the syntax to make it work? 

In my perspective, your cmdlet will work regardless of the membership approval settings (Closed, Owner Approval, or Open) as long as the user running the command has the necessary permissions. The BypassSecurityGroupManagerCheck parameter is specifically designed to override these membership approval settings. It allows a user with the appropriate administrative roles (such as Organization Management or Recipient Management) to add or remove members directly, bypassing the typical owner-approval workflow. 

3.If the DL owner field is blank, I believe the above syntax will not work. How can I add myself as the DL owner and also add members to the DL? 

As previously mentioned, users with the appropriate administrative roles can add or remove members directly, without needing to be the owner of the distribution list. 

However, you can refer to the following cmdlet to add your account as the owner of the distribution list: 

Set-DistributionGroup -Identity DL ******@domain.com -ManagedBy 

I will be waiting for your response. If you need further assistance, please  let us know.

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